Clubs were bankrolled by businessmen, it was the model at the time and United benefitted from it greatly and more than most clubs at the time. I don't even see why you try to give mitigating factors that are irrelevant, I'm not making a critic of the situation. But United were an unsustainable club saved and then bankrolled by local businessmen, the club capitalized on that and through great management became a mastodons.Yes but that went towards paying the clubs debt, it wasn't spent on players. Yes the chairman paid for the construction of a 100,000 capacity Old Trafford but money for investment wasn't unlimited. The club tried to get a rail company to subsidise the costs of construction, when that didn't work out the plans for OT were scaled back to 80,000.
Now I'm not claiming United didn't get some financial help back then, most football clubs that still exist today have had help at one point or another. But my only point is that a few local businessmen investing £500 each at the turn of the 20th century is in no way comparable to Oligarchs and Nation states pumping unlimited billions into clubs in the 21st century.
It is absolutely comparable in football the spendings of PSG, City or Chelsea aren't actually that different from the spendings of other big clubs. As much as people want to be outraged they have not spent amounts of money that aren't in the realm of Football.