In spite of Liverpool's dominance in the late 70's, thirteen different clubs won the First Division between 1960 and 1981, including the likes of Burnley, Ipswich, Forest and Derby.
There was a reason for this; the TV and gate money was split along fairly equitable lines. In terms of gate receipts, it was a system that had been in place since the 19th century and ensured that money was redistributed throughout the game in a manner that tried to create a level playing field, as much as possible.
Some clubs were uncomfortable with this. Some clubs thought it was unfair that 'smaller' clubs were benefitting from their larger supporter-base and so they took steps to address it. Five clubs in particular took it upon themselves to reshape the way that finances in football were distributed: united, Liverpool, Everton, Spurs and Arsenal. It started with Football League gate receipts in the early 80's, thereafter allowing home clubs to keep all of the receipts from ticket sales in league games (the old rules remaining in the FA Cup). This clearly benefitted the larger clubs with bigger capacities. The way that TV money was distributed was next, in terms of the terrestrial deal - more money would be kept by those at the top, at the expense of those at the bottom. However this didn't go far enough for some clubs and so a few years later a breakaway league was formed, The Premier League, with the top division keeping all their TV money to themselves. Throughout all those events, certain clubs threatened to go off on their own if their demands weren't met. Principally, the same five that made the moves around gate receipts, although tbf, other clubs, City included, were either compliant or acquiescent with the direction of travel. There was lots of money to be made, after all.
All these moves were designed by the 'top' clubs to concentrate more and more money at the top of the English game. It is concomitant of this approach, that those at the bottom would receive less, at least in relative terms. These clubs sought to enrich themselves by changing the rules to favour themselves, and it is undeniable that for them, it worked and enabled them to 'earn' their money 'the right way' for a sustained period.
More and more money flooded into the upper echelons of the English game, as a serendipitous cocktail of global media and technological advances conflated to create a perfect storm for those who were prescient enough to engineer their own good fortune at the right time. And it worked wonderfully for a number of years. The rich got even richer, on and off the pitch, whilst the rest of the game barely managed to keep its head above water. However, as the Premier League brand and the reflected glory that accompanies it continued to grow, people outside the party started to want a piece of the action. People like Roman Abramovich and Sheikh Mansour. Why wouldn't they? I know I would if I had that sort of dough.
What we are seeing is quite simply the natural outcome of the decisions that were made in the early 80's. Create a sufficiently large honeypot and it will draw attention. Concentrate enough money in a particular area, then predators will circle and want a piece of it. It isn't particularly complicated or unexpected.
Perhaps if supporters of the foregoing 'Big 5' made the effort to research the subject, they would realise that it was their clubs' naked greed and own form of financial doping that created the landscape for the Sugar Daddies they decry to want to (and be able to) enter the fray. If they'd left well alone, and kept spreading the wealth around, the English game would still be wholesome and trophies would be spread out more evenly, which is something I'm sure they'd all greatly welcome - except they wouldn't, of course.
If you change the rules to suit yourself, don't expect that advantage to last forever.
And be careful what you wish for.