Yes a lot of money has been spent by United but the managers since Sir Alex weren't getting the players they wanted.
That's clearly not true at all though is it.
Almost every signing we have made under Moyes, LVG, Mourinho and Ole has been
manager-directed, bar a handful that were effectively scouting department signings - Shaw, Herrera, Fred, VDB and Martial. Mourinho was offered Fred and said yes, that's on him. Ole was offered VdB and said yes, that's on him too. The deals for Shaw and Herrera were in the pipeline before LVG took over but he probably could have vetoed them as well if he wanted. The scouting department really came through for LVG with those two and Martial, they were by miles the best signings under his tenure.
The only signings we have made that were "Woodward signings", or vanity signings, were Mata, Falcao and Sanchez. Sanchez was a ridiculous wage packet but given he was one of the best players in the league for the previous two seasons, I think it's safe to assume bringing him in wasn't against Jose's wishes either. Mata was signed for Moyes' replacement rather than for Moyes himself, he was already doomed by then from the boards point of view.
All the other unsuccessful signings were players the managers asked for. Di Maria, Depay, Rojo, Schweinsteiger, Schneiderlin, Darmian - all on LVG. Pogba, Mkhitaryan, Matic, Lukaku, Dalot - all on Mourinho. Dan James - very much an Ole signing. That also goes for signings that the jury is still out for like Bailly, Lindelof and AWB.