When a player feels good, it's difficult for him to give up. Also in other less remunerative contexts, for example in normal work: if you get on well with an employer, you will hardly change jobs and risk finding a hostile environment.
Staying in Seria A allows Dybala to continue to receive calls from the Argentine National Team, if joining the SPL is not possible at all.
Ah! incredible. I didn't know this, so he also does it for his personal convenience (he's in)
I don't understand the reason not to call in the SPL, but if they have decided so, just adapt (to this rule) to be able to play in the national team too