If you look at the clubs in that big 5, Man Utd are the real outliers, in the sense that they were a northern club (so couldn't rely on London based income in the way Spurs and Arsenal have done), yet have built a money making machine. Ok that's being exploited like you wouldn't believe by the owners, but the build period is what we're talking about here right?
I think a major reason for their success during the early Sky period was that they were listed on the stock exchange and had good management (board level that is). I was a shareholder in them back then so got regular updates on what they were doing and how effective it was. Like them or not, they generally went about things the right way.
They used money from the flotation and from Sky to invest heavily into Old Trafford. You have to remember that after the Taylor report, Old Trafford only seated 44,000 fans, so not much more than Goodison. It was also a stadium with a similar age to GP.
To coincide with hosting games at Euro 96 they bought a nearby trading estate to give them space to expand the ground. First they added 10,000 seats, taking it to 55,000, then when the next stand was finished it had risen to over 68,000. Of course now the stadium holds 76,000 or so fans, nearly double what Goodison holds.
So that was one thing. They also invested heavily in the training and youth facilities, and have led the way in terms of growing commercial revenue.
Whilst we built Finch Farm, that was delivered 7 years after Man Utd re-built Carrington. Our commercial revenues, especially from overseas markets, has also been well behind.
They should have been the role model for us, because they haven't grown due to sugar daddy spending, they've grown due to their own revenue, and if it wasn't for the Glazers they would be so much better off as a result.
Of course things might have been very different had that Knightly bloke bought them as he'd wanted to.