The late Martin Crowe was right. In 2014, the former New Zealand captain raved about a quartet of young batters, all of whom shared common traits. “All four have similar talent, hunger, ambition and responsibility,” he wrote in ESPNcricinfo. All four, he added, would go on to captain their countries. All four, he sensed, would have a go at being the No.1 Test batter in the world. Virat Kohli, Steve Smith, Kane Williamson and Joe Root were the future.

And how they delivered. Root is just a knock or two away from 10,000 Test runs, while Smith’s name closely follows Bradman’s. Kohli is arguably the biggest star the game has to offer today, and Williamson will end his career as New Zealand’s finest. All four have made sure they’ll be remembered as kings of the modern era.

But these are strange times for the Fab Four, with each member feeling the strain of mortality. The runs haven’t completely dried up; in fact, the youngest of the lot has been in astonishing touch since the start of last year. But the world doesn’t revolve around them anymore. Others can lay claim to being the best, and Williamson is the only one who continues to bark the orders. Wear and tear is starting to show.

Kohli has endured the most dramatic slump. For the longest time, he was the man who made all the noise, the heart-on-sleeve captain and all-format conqueror who had 69 international hundreds before turning 31. But it’s been 29 months since his last ton. The mastery still crops up once in a while – his 79 at Cape Town this January combined resistance with a compilation of stunning drives – but that astonishing consistency has disappeared. Such electric dominance across all three forms was always going to be difficult to maintain in the age of Covid.

Power has moved into other hands too. With Rohit Sharma India’s all-format captain and Faf du Plessis leading at Royal Challengers Bangalore, Kohli is now back in the ranks. “I’ve done the job with absolute honesty and left nothing out there,” he said when he gave up the Test gig. Now the intensity of leadership is out of the picture, will the regular flow of runs return? Kohli’s recent struggles in the IPL suggest it’s not that simple.

Perhaps it’s worth listening to Ravi Shastri, who worked closely alongside Kohli for years as India’s head coach. “He’s overcooked,” Shastri said on Star Sports last week. “If anyone needs a break, it’s him who needs a break. Whether it’s two months, a month and a half, whether it’s after England [where India tour in July], whether it’s before England – he needs a break. He’s got six, seven years of cricket left in him. You don’t want to lose that with a fried brain.”

Williamson still leads for New Zealand (and Sunrisers Hyderabad). Quiet and forever unreadable, he’s always come at the world differently to Kohli. In 2021 he was out there in the middle as New Zealand won the World Test Championship, and his 85 in the T20 World Cup final was an in-vain innings of the highest quality.

But his year was also dogged by a persistent elbow problem, one that had to be constantly managed. When New Zealand toured India after the World Cup, Williamson was forced out of action after one Test, and he hasn’t played for his country since. Tom Latham wore the blazer in Williamson’s absence during the home summer as New Zealand failed to secure a Test series win. The 31-year-old remains his country’s main man, but not everything’s gone to plan of late.

Smith’s had his own elbow problems, and injury ruled him out of Australia’s recent white-ball matches in Pakistan. Before that, though, he enjoyed a solid Test series, hitting three half-centuries in four innings to help seal a historic 1-0 series win. But it’s still hard to not think about what he once was. For more than half a decade, the fidgety genius rewrote the rules and failed to go more than four Tests without a hundred. He dealt with scandal and came back with twin tons at Edgbaston.

Yet the game has become more of a fight. Strike rate, average, the frequency of centuries – the numbers have all dipped in Test cricket since the end of that staggering 2019 Ashes campaign. Not catastrophically by any means, but Marnus Labuschagne has overtaken him to take top spot in the rankings and Usman Khawaja was Australia’s headliner in Pakistan. Smith still averages 48.31 in Test cricket since the start of 2021, demonstrating his importance to the Australian set-up. But that sense of invincibility has slowly dissipated.

Root has occasionally been cast as the Andy Murray of this conversation, fighting to make sure the four isn’t reduced to three. Yet he was immense in 2021, hitting 1,708 Test runs at 61. That old problem of conversion went away as he made six hundreds in 15 Tests, and this year began with back-to-back tons in the Caribbean. But for all of his excellence, his team lurched from one debacle to another. A 1-0 defeat to the West Indies had to be the end, and Root knew it, giving up the captaincy earlier this month. Like Kohli, it’s now time to focus solely on the batting.

But is it realistic to expect the 31-year-old to continue his hot streak and break all sorts of records? Alastair Cook – Root’s predecessor – was 32 when he quit the captaincy; he too had time on his side to go on and enjoy his career with less responsibility. Just 19 months later, though, Cook announced his international retirement, admitting that there was “nothing left in the tank”. And unlike Root, he wasn’t balancing Test cricket with white-ball duties for England. For all of Root’s recent success, there are no guarantees with what comes next. With the amount of Test cricket England play, it doesn’t take long for a purple patch to turn into a terminal rut.

In recent years, some have threatened to join the club – Babar Azam continues to excel in every format. But this group has never solely represented the best batters in the world. It was a band of prodigies, separated in age by just a couple of years, striving to become something more. Kohli and Williamson were both captains when they took on each other in the semi-finals of the 2008 Under-19 World Cup, while Root and Smith became Test centurions in the same English summer. They all got over their minor bumps at the start, rose to the top, broke records and secured their legacies.

There are gaps in the CV still left to fill, and maybe that’s something to keep an eye on. Kohli has never won the T20 World Cup, which will be up for grabs in Australia this year. Williamson and his teammates have finished runners-up in two consecutive 50-over World Cup finals. While Smith helped Australia retain the Ashes three years ago, they still haven’t won a Test series in England since 2001. After three tours, Root has tasted 12 Test defeats in Australia and not a single win.

As Crowe wrote, they all had similar hunger and ambition as youngsters. Now they’ve made their mark, is there still enough to keep going? Things will get harder from here, even if experience is on their side. Bodies will grow weary, and younger, fitter, faster acts will have their say. They’ll have to think about what formats they want to play, and if things aren’t going well, will others make that call for them? Who retires first? Who will be the last man standing? Suddenly, we’re in uncertain territory, at a point where these four paths finally diverge. One or two could return to the top of the Test batting rankings. All four of them? Highly doubtful.

We’ve entered the final stage of the Fab Four era, and it’ll be a shame when it eventually comes to a close. But we can console ourselves with the hope that this could yet be the most intriguing phase of all.