You're trying to move the goalposts from what you originally said.
"Yeah football was much better when you could dominate the spending on your own with no competition except Arsenal right?"
That situation never really occurred. There have always been teams spending around the same and generally more than United during the premier league era. Look at Newcastle's spending over a 4 year period, spending over £90 million and in those same years we spent around £46 million. Look at Blackburn's spending, or Arsenal's, Liverpool's, Chelsea's, Leeds' over a few years. There were always been clubs willing to spend big.
Even if we go along with the whole United were dominant in the market just before Chelsea were bought out, we had spent around £138 million in those 5 years, the teams around us had £93m (Arsenal), £97.5m (Chelsea), £111m (Liverpool), £104m (Newcastle), with most of them having outspent us for years before that. Transfer league is broken for United so if I get time I'll do net in the morning.
We didn't quickly catch up to either Chelsea's or City's spending, it took both of those clubs slowing down their spending for us to start getting close to them. Both Liverpool and Spurs outspent us (similar net spends) during the first 4-5 years of Abramovic at Chelsea. How could that even possible if we were able to dominate them financially?