In a phrase which sounds authoritative but radiates helplessness, the Premier League declares itself "ownership neutral" meaning it has no preference for any structure on which England's great football clubs have come to be orchestrated. So the Manchester derby, which could decide the league's destiny in its 20th season, was among its myriad themes a contest between one club, City, whose owner has invested £1bn, and the other, United, the Glazers have drained of £500m.

Margins are fine, City's victory was only 1-0, they lead by just goal difference, two games remain and United, as Roberto Mancini continues to insist, could still win it. Yet Sheikh Mansour bin Zayed al-Nahyan's squad of world‑class players assembled for Mancini, faced a United of veterans and promising youngsters who suddenly looked the product of the Glazers' taking culture.

The eyewatering £500m has been paid out of Old Trafford, from money forked out by fans in increased ticket prices, and TV and commercial income, to pay bankers, lawyers and accountants black holes of interest, fees and one-off charges. It has poured out in just seven years from the Glazers borrowing £525m to take over the greatest of clubs, then making the club liable to service their borrowings.

Sir Alex Ferguson has maintained success in that period, winning the Premier League four times and the Champions League, and the manager has confounded the fans protesting against the Glazers by repeatedly singing their praises. David Gill, United's chief executive, part of the board which opposed the Glazers' hostile bid in 2005, has afterwards said the takeover was restructured and pronounced himself happy with the debt burden.

The Glazer family's original plan was to register the famous Man United in the low‑tax US state of Nevada and one day make money for themselves by selling it or floating it on some stock market. They always knew they needed United to remain successful to achieve financial gain, and did always budget, along with the oceans of interest they would drain from the club, to provide Ferguson with £25m or so a season to replenish his squad.

They have been true to that strategy, and last summer Ferguson spent more than for a long time: £18.9m on David de Gea, £16.5m on Phil Jones, who played uneasily at right-back in the derby, and £17m for Ashley Young, brought on as a late substitute. It is difficult to pin a diminution of the manager's transfer horizons on the Glazers' arrival; he has always been prepared to break transfer records on the best British talent, from Gary Pallister to Rio Ferdinand, then sought to sprinkle in class from overseas.

Some of his marquee purchases have not vindicated their cost, notably Juan Sebastián Verón and latterly Dimitar Berbatov, but Ruud van Nistelrooy did, and Cristiano Ronaldo, at £12m, proved unbeatable business. After Ronaldo left in July 2009 for £80m, the signings have seemed to become less ambitious. There was an acceptance that Ronaldo could not be replaced and United, for some reason, were not in a financial league to compete with the galácticos of Real Madrid or the pass masters of Barcelona who outclassed United in two Champions League finals.

To assess the impact which the Glazer takeover has had on the club, besides rising prices and the automatic scheme which forces season ticket holders to buy a seat at every cup match, it is always instructive to imagine United had the Americans never turned up in the first place. Flush with the largest turnover in the Premier League, with profits of £50m or £60m, paying relatively modest dividends as a plc compared to the Glazer leverage, it is difficult to imagine Ferguson being satisfied with the side he has. It is hard to think of him not aiming to build on Premier League dominance, and, while admirably continuing to promote young players, straining against Barcelona to become the best in Europe.

This season United were knocked out of the Champions League in the group stage, Athletic Bilbao wiped them out of the Europa League and now the Glazers' club need City to drop points in the Premier League.

When the "mind games" began a month ago, United's manager scoffed at Patrick Vieira, the City ambassador who had described as "desperate" Paul Scholes pulling the boots on again. Ferguson retorted that Mancini's re-acceptance of Carlos Tevez was more desperate. Yet there was a huge difference. Tevez, 28 and at the top of his game, has been reintroduced after a drawn out clash with Mancini. Scholes is 37 and came out of actual retirement for the central role of anchoring United's midfield. There he was overcome by the colossus of Yaya Touré, 28, a Champions League winner with Barcelona, signed by City with £24m of Sheikh Mansour's money, from a menu of choices requested by Mancini in 2010.

The Abu Dhabi "project," while sending City fans ecstatic on Monday, is, of course, widely disdained in football as the buying of success, contrary to the gradual building of a team from a club's own resources which Ferguson, for all United's money, has previously achieved prodigiously. Before Mancini can consider leaving the legacy he says he seeks, and a long-term passing of Manchester football power is contemplated, City must face Uefa's financial fair play from 2014, its aim to restrain such massive overspending even with an owner's subsidy.

That is for then. For now, United fans forking out for tickets may again begin to question forcefully the claim that £500m taken out of their club has made no difference, an argument which for seven long years has been an insult to their intelligence.