I don't think anyone in the world currently can get into it other than maybe Kohli. It's too early to say.
See people like to bring up Williamson and Root, and while they have been solid in tests they've only recently been finding LOI success. And to get in this league you have to be proficient in ODIs and tests at least.
Kohli's been around longer (IIRC??) and has been established longer than them, think he's in the league in ODIs, but not in tests, but it might be a matter of time, or he may never reach it, let's see. Has the killer instinct.
Personally I think Williamson is a weak character and doesn't have the fire or killer instinct to reach this league.
People say Smith looks bad and like a hack, but he has this killer instinct, think it's built into Aussie players. Yet to see a meek Aussie. He's willing to do whatever it takes to win, and is not afraid to take calculated risks in his batting (like that outside the off stump flick to Wahab) something I don't see Willy doing, he's too conservative.
Before anyone says "but but Virat doesn't take risks", yeah he does, they're not wild risks, but calculated ones. I.e. letting the run rate creep up in the Aus game, it was a risk, but he had to bank on the belief in himself that he is good enough to catch up with the RR near the end, which he did.
So yeah. Virat might reach it, Smith may as well, but a long shot. Don't think Williamson will reach it IMHO.
Root I think it's too early to say because it's only been a few months I think that he's getting into the groove in limited overs cricket. Was awesome at the world t20, and in ODIs as well. He's a bit like Williamson in that he lacks killer instinct and is conservative at times. But the Root we saw at the WT20 looked different and like a man who was willing to take risks, albeit calculated ones.
One guy people are glossing over yet is easily the 2nd most destructive limited overs player in 2016 IMHO, is Quinton de Kock, aka Q-dock. Honestly, this kid seriously looks like the real deal for me, and yes I know it is waaay too soon to call, but if he can keep up the hunger he has these days he will at the very least get close to this league if not breach it. He is South African, which goes against him, as he has to fight the choker tag, BUT, he looks the least likeliest to choke. In fact, he is the only clutch player for SAF in LO crunch situations.
His range of shots is more vast than Smith and Root IMO, and he "reads" the game like Kohli. (just look at his chases, especially the rain hit game vs Eng chasing ~350). Terrific player to watch, but like Kohli, needs to improve in tests. Actually, he's kinda like Kohli jr. in LOIs.
So yeah IMO, this is how I'd rank today's players as most likeliest to reach SRT-Lara league:
1) Kohli
2) Q-dock
3) Smith
4) Root
5) Williamson
6) Babar Azam
Thanks.