Your first paragraph was emphatically proven wrong by Gundo in the season finale v. Villa. He freely admitted afterwards that he was hoppin' mad about starting on the bench yet he responded with a title saving performance. Bernardo stepped in yesterday after not starting in the first 2 league games and responded with a goal and an assist. You can't make generic statements based on your own beliefs and expect them to be accepted as fact.
Your second paragraph is even less factual. Cancelo signed on knowing Walker was here and established. Phillips just did the same relative to Rodri. Grealish signed when Sterling and Gabby were still here and well established to go along with Mahrez and Foden. Your theory here may have some validity with some players, but I wouldn't want to sign a player not willing to back his own chances anyway. A guy with that mentality would not make it here.
Its a fact that we are a bit light in numbers relative to other big squads. Whether that winds up costing us or not remains to be seen, but your reasons for maintaining a smaller squad are unfounded. Just sayin'.