There might some truth. Our top players might have a measurable dip in production after playing 32 minutes or whatever.
If one were to express the merits of platooning and/or depth before the season started, then they must then also concede there is some drop off in player production after playing x minutes. Otherwise, why sub at all? Much less sub so deep as to have two units or play 10 players.
We intuitively understand that players might get worse the more minutes they play. There exists an optimization of minutes between, say, Oweh and his sub. Maybe it’s 35 minutes for Oweh and just 5 for his sub. I don’t know that off the top of my head.
It’s only a big deal because Pope mentions it in press conferences. If there exists an optimal amount of bench player minutes that’s greater than zero, then stating starters make mistakes because they are tired is really a backhanded way to say our subs suck. We play starters longer than their optimum out of necessity because our bench is terrible. It’s a polite way to deflect ire from poor bench production.