I mean honestly who does this not apply to at almost any other club that is paid to be a starter? As I noted in the transfer thread we're seemingly the only club in the world where more than 5 midfielders is even a discussion point. Is there a player on another club where the fan base is making excuses for him that he had to play too much?
I think we can all acknowledge that generally the players are asked to play too many games while also noting that the demands on our players aren't hugely different than any other CL level team. If we ruined them then there is no one else to blame and then it's more of a choice of do you want to just continue to pay them for sentimental reasons or do you just bite the bullet and move them on?
Fabinho has actually played a more reasonable amount of football than most of our players - he's played nearly 30% less football than Robertson since signing for us, for example. He plays a very similar amount of minutes per season to comparable midfielders at other clubs - in fact less than Rodri, Jorginho, Bernardo Silva, Gundogan, etc.
Fabinho's problem is he's never been the quickest/fittest and he seems to be slowing down as he's aged (both in terms of covering the ground and reaction times) which has been compounded by general midfield dysfunction. It's fine if you play to his strengths (of which he has plenty) or surround him with runners, but it's become increasingly easy to take him out of the game, particularly on transitions, and that's a concern for us with the way we play and given teams are starting to play a bit more bravely against us (particularly in terms of committing men forward on the break).
He will look better if/when we start penning teams in again, or if we ever buy an athletic midfielder, but I think we'll see a lot more of these types of performance unless we change the way we set up. He just isn't very good at covering ground when running back towards his own goal. It is what it is.