You might be able to argue that we've underachieved since the takeover, but I'd dispute the 'hugely' aspect completely. Success was never going to be instantaneous, and given that we first had to attract virtually a whole new squad of players capable of realising our ambitions, the fact that it took us 4 seasons to win the Premier League for the first time was far from unreasonable IMO. Our triumph that season was also a significant catalyst for the League's boom in popularity, with the financial advantage enjoyed by the rags, the Arse and the dippers, courtesy of 15 odd years unbroken Chimps League prize money, greatly reduced as successive new domestic TV deals outstripped CL earnings. In short, the league became far more competitive post-Agueroooooo than it had been pre-Agueroooooo, yet despite that we finished 2nd, 1st and 2nd in the 3 following years.
Had the press applied a modicum of consistency then their criticism might have carried greater justification, but they didn't. In fact from 2008 to 2012 inclusive, they did nothing but parrot the line that "money can't buy success", because to have taken an alternate stance would have effectively denigrated Taggart's achievements at the Swamp, the long standing narrative being that united's success was due to his brilliant stewardship rather than the fact that they had 5 times as much disposable income as anyone else in the league.
I don't go in for the some of the absurd claims of bias on here, that because Alan Shearer sat in a red chair on MotD it constitutes evidence of an agenda against us by the BBC and so forth, but I find the dismissal of all accusations of bias against City equally ridiculous. The media (and particularly the print press) is now driven almost exclusively by the concept of clickbait and associated advertising revenues. If you take a paper like the Mail, whose online version has one of the biggest readerships on the planet, you will note that literally every story has a comments section and a provocative headline. It caters for the largest demographic it can side with on every occasion, and City, as a footballing usurper which has directly and adversely impacted the income streams and trophy winning potential of some of the world's best supported teams, come gift wrapped as the bogeyman in chief. To deny otherwise is to deny the power of advertising. The tone may change over time as we build a global fanbase of our own and further cement our position at the top table, but that time is considerably further away than the memory of a national broadcaster (BT Sport) actively hoping an English team (City) would lose in the Champions League and setting out its stall in that regard to appeal to casual armchair rag viewers in the expectation that there would be more of them watching our games on the telly than there would be City fans.