Would their fans be ok with a couple of seasons in mid-table like Arsenal? Would their fans be ok with a long-term drought like we went through after 1990? See there's no god-given right for them to have to have been on top forever.
Their fans want the shiny object, and they revel in being the "biggest club in the world" or whatever (shirt sales) so really is it not a good fit with the commercial ethos of them being as much of a "brand" (ugh) as a football club? I feel they would probably feel that signing a player like Cancelo, Rodri or Jota was actually beneath them, they'd never make those signings. A "club of their stature" needs to be signing the best English right-back in the game (Wan-Bissaka), the best Brazilian midfield name available (Fred) and the best English attacking name available (Sancho). They're basically about names. Very much loud car with loud exhaust overspeeding down the city street energy.