The first problem is a team problem and why I mentioned balance several times, you need to adapt to your own team, hide its flaws and expose its qualities, create your own balance. The second one is not necessarily a problem, not all players have to run the same amount because they don't have the same roles or the same attributes, for example Pogba had far better creativity stats than Liverpool midfielders and was close to Liverpool most creative players(if I remember correctly) and it was fine for them because their creativity came from their fullbacks and front three. As for the attackers it was an issue for us because they weren't compensating it with end product.
Now I can make a step in your direction in saying that every player needs to provide something, for example our attackers can't be "lazy", they are not clinical or creative enough for that. Pogba needs to create a lot in order to justify his role, if he doesn't or if his creativity can be provided by our front three and our fullbacks then we will be in a positon to claim that he can be replaced by a hardworking midfielder. But this has nothing to do with modern football, it's a simple matter of balance, that's why I'm not against the idea of selling him if it allows us to finance a different approach. The only issue is that currently Pogba isn't the odd man, there isn't an approach that is one Pogba away from success, we are missing are numerous enough players that it allows us to create anything with the corerct purchases.
I will say it one last time and we should move on after that. We do not have to play like City or Liverpool, there are many ways to be successful in 2019, Pogba doesn't have to be like Wijnaldum or De Bruyne, De Gea doesn't have to be like Ederson and Allisson. Martial doesn't have to be like Aguero or Firminho. Like every teams we need to be creative and defend well, those things are done with 11 players.