Yeah, the investment in City was very inconvenient indeed to the oligopoly it broke.
It didn't really break an oligopoly though, did it? Just started a new one, but with mega-rich and extremely dubious owners.
Chelsea got there first, obviously. As an Arsenal fan I'm particularly aggrieved, because if we were part of an oligopoly we did it under our own steam. We did it by ending Liverpool's dominance in the eighties and by challenging the superpower of Man Utd in the nineties/noughties. To be competitive with Man Utd we built a new stadium, redeveloped the old one (listed building so we couldn't just tear it down, thankfully) and did some associated development of flats and offices - all without a sugar-daddy, just standard loans from banks.
Our reward for that was the arrival of Abramovich, who "parked his tanks on our lawn and is firing £50 notes at us" as David Dein said at the time. The half a billion he splashed out then was a ridiculous amount of money for the period. Instead of a new golden age in the new stadium, our Invincibles were the last time we won the league as the Chelsea domination (interspersed with some continued Man Utd dominance) started. Then Sheikh Mansour arrived at Man City and suddenly we have to sell our players to keep up the mortgage payments - Clichy, Kolo Touré, Adebayor, Sagna, Nasri went to City - that's half a team.
The massive inflation in player transfer fees and wages caused by Chelsea and City wasn't really possible to compete with, and we dropped from being 1st/2nd to 3rd/4th and then out of the top four entirely and playing in UEFA League instead of Champions League.
I guess some people will think this is a good thing, but I think it's fundamentally broken football. I think both Liverpool and Arsenal lost out on titles to a couple of smaller teams that just happened to win the oligarch lottery. Where we had to compete with the spending power of the Man Utd machine and its global merchandising suddenly we had to compete with teams with bottomless pockets. It gutted English football and opened it up to foreign billionaires (e.g. Dein sold his shares to Usmanov in a bid to get a billionaire on board, but the rest of the board were unimpressed and sold to Kroenke to stop him. Usmanov is currently sanctioned along with Abramovich, having also buggered around with Everton, and eventually we're under sole ownership of Kroenke, in a forced buyout that removed shares from independent Arsenal fans).
And yes, we've spent a fortune on players the last few years, but we've done it within the rules, and we've been limited by them. And maybe one day we'll find out what happens with those 115 (actually 134 now btw) charges. I don't hold out much hope, though precedents have been set with other teams now. I doubt we'll see an open top bus ride for a title awarded retrospectively anyway, the ultimate irony would be to hear you won a title without any of the joy of actually winning it - that's a proper robbery. Bitter? You bet.
Anyway, 3 pts V Sunderland yesterday (still as many titles as Chelsea) and hopefully City lose to Liverpool today and we might be on our way to our first title since 2004.