Manchester United supporters would not object if the Glazer family abandoned the team they controversially acquired ownership of in 2005 and vanished into the sunset. Only resentment that they divided the match-going fanbase, piled on a lot of debt to the club after a heavily leveraged buyout, and kept pocketing millions in dividends regardless of field performance. The lack of regulation in England's Premier League, the most watched domestic football league in the world, was demonstrated by the fact that the takeover was even permitted to take place.
Cristiano Ronaldo announced on Tuesday that he will be leaving the team with immediate effect, and immediately after that, Manchester United released a 346-word statement with the headline "Manchester United launches procedure to investigate strategic alternatives to boost the club's growth." That basically says United are up for sale when translated. The Glazers would "explore all strategic possibilities, including additional investment into the club, a sale," since the club needs major investment, most notably to their Old Trafford stadium and training facility.
Before the Glazers arrived, United was at the forefront of stadium renovations and infrastructure, but under their leadership, they dropped to the bottom of the pack. Between 2005 and the fallout from a disastrous decision to join a potential European Super League in 2021, they didn't interact with fans. The Glazers, along with Barcelona and Real Madrid, bet big on the extra money such a league would bring in, but fan protests put an end to that.
The Glazers' whole ownership of United has been characterised by opposition. From a business standpoint, their takeover was legitimate; but, football clubs are more than just figures on a balance sheet. Manchester United, one of the top three clubs in the world, may attract attention on a worldwide scale, but at its core, it is a local football team with long-tenured employees and devoted supporters.
The Glazers have been considering a possible purchase or sale since the summer, so this choice has been made for some time. Ronaldo's contentious interview with Piers Morgan last week has nothing to do with it.
Potential suitors will be contacted or made approaches when advisors have been selected. United is hopeful that they can generate more interest than Ronaldo did when he made it known he wanted to go during the summer. Ronaldo would have set the club back millions of dollars.