If your feet hurt, you change how you play. You stop pushing off. You stop planting hard. You start managing the shoe instead of the point.
That's how a pair lets you down even when it hasn't ripped yet.
What players actually feel
Blisters on the heel or pinky toe. An arch that folds when you plant. Numb toes. Pain that makes you skip the third set.
A lot of tennis shoes still put a hard board under the foot and call it support. The pain starts in set one. By set three you are done, even if the match isn't.
What has to change
Cushioning that absorbs the baseline pounding without turning into mud. An upper that locks the foot so you don't slide around inside and blister. Rubber that is still there in month four, so you aren't buying a new pair every time the outsole balds.
Shoes should disappear. The point should stay yours.