Indeed, it must be admitted that Zidane's capacity is not for PSG and of course he is well aware that if he manages PSG there may be a number of things that make him quite depressed. On the other hand, Real Madrid will still be his top choice and it is possible that if there is an offer, maybe from an Italian team like Juventus, who also used Zidane as a former player there.
I think it will be more limited for coaches next season and it seems that they have no other choice but to bring in Luis Enrique, after all he is also a very experienced coach in Europe and even brought Barcelona to win so many trophies at that time.
The problem is that he managed very very small amount of time and quit, even quit while he was managing and cameback and managed some more and left again, in all of those years he won UCL and been a great manager and wrote his name in the world legends as a manager, just 3 seasons and he is already amazing.
So, when you consider the fact that he might have to actually end up with coming back, and ruin all of that just for PSG doesn't seem like it makes sense. Think about it, he is considered a great player and a great manager so far, why not be remembered that way and just leave the sport all together? He has tens of millions of dollars and amazing investments, why need to risk it all for PSG and maybe lose everything you have collected so far?