...Nada. It's bullshit. They can't sign players to improve the XI or the squad depth 'cause they have difficulty finding buyers for their average players with high wages, some on long-term contracts i.e. Phil Jones (3 years left!!), Rojo.
Bale, i get not signing him; past his prime, injury-prone, has to play in a high-intensity league and also on high wages.
Reguilon, however should be signed even with the buy-back clause, because he's clearly a better option at LB than Shaw. If his value increases and RM sign him back, that will likely coincide with United playing well and having better success in league & cup comps.
This will be a far better appeal to other top players, than the prestige & allure of the United name/brand. So their desired replacement for Reguilon will be a more realistic target.
Having an injury-prone Shaw, who's underwhelming going forward and decent defensively, isn't likely to produce a better end result in league & cup comps than in last season.