Ok, here's how I see Dybala as someone who follows the league pretty closely. Feel free to disagree , as I'm sure many of you will - it's just how I perceive things.
Dybala's a lovely player to watch, plays through the lines really well , scores some excellent goals from distance and overall his goalscoring record is really good for being more of a second striker/10. He's genuinely a very talented player - and a bit of a throwback , which I happen to like.
few problems:
1) Signing Ronaldo, for all his greatness, means other good attacking players have to become mere mortals again and sacrifice. He's clearly suffered from that. The reason you see Mandzukic , is the same reason you saw Benzema. It's not that Allegri's a moron , or that he doesn't like Dybala, it's the fact he's doing what any good manager does and he's building what he deems a functional side around a historically good player. I know people love to rag on Higuain here (and he's been bad in London , for sure) , but his chemistry with Dybala was miles better than Dybala's with Ronaldo.
The Ronaldo signing changed everything for Dybala at Juventus. This should be clear when Dybala's had prolific seasons under the same manager.
2)5 Serie A goals this season in 27 games. You can't honestly blame the manager for all of it. Sure, if you want to put some of it on Allegri - I'll agree. But he's also just straight up not playing well. That's the damn truth. Watch the Spal match and tell me it's all on Allegri. Hazard would be crucified by the English media if he had a season like this (as was the case in 15/16).
3) He simply can't establish himself at international level. Frozen out as it was assumed him and Messi couldn't function in same 11. So that's now both Messi and Ronaldo managers have deemed he can't co-exist with. Yes, I know Argentina is not a model country in terms of their national program. Frankly, it's embarrassingly bad at times from what I've read/seen. But is there something to it? Yeah, I would suggest there probably is.