Sure, but we don't really have anything to judge Allegri on in the PL. If he has players who suit his philosophy then Kulu in an Allegri Spurs team could theoretically do well. It depends on the type of players you get in.
It's easy to say now that Allegri is the worst coach ever and will struggle to get a job at Pizzighettone after this stint but this whole scenario has been created by the club, it's failed, and they have dug themselves into a hole where it seems the coach has lost the players, and the club can't afford to sack him. All Allegri has done is reverted to type and made the team rigid and lacking in taking many risks. The players are now afraid in all areas, and we dont have characters.
Players like Kulu, and it seems a lot of modern players, perhaps need clear guidance every step of the way from the coach, they need motivation, or else they just coast along. Not all players are like this but it does seem more prevalent in modern players. Allegri now doesn't have a Vidal, Lichtsteiner, Chiellini or Tevez dragging the team along or interpreting what he wants, and I'm afraid you can't expect Kulu or Bentancur to be those players to do that with Juve. At Conte under Spurs with a fire under their asses yes great, but even then this routine only works so long. I think Conte well understands this too, and some players just don't take to it either. They aren't robots.
I don't at all regret Kulu leaving, but I understand why the anti-Allegri people (and admitted trolls) want to go around all the threads and say "look what Allegri did", when it is also the responsibility of the club's poor recruitment choices and the players themselves. I mean, if Alex Sandro goes to Spurs on a free and looks like prime Marcelo are we going to say that Allegri ruined him? I wouldn't even be surprised. He's simply yet another player going through the motions playing "big club player". Ultimately the players are the ones who play the 90 mins and control the destiny of coaches. Our current issue is that Allegri should have either not been brought back (shout out to all the Captain Hindsights out there) or he should have been replaced by now. As usual the club doesn't have a contingency plan.