It's bizarre all these players that United were paying huge wages to just bombing or retiring at much lesser clubs, Martial, Lingard, Varane, Pogba, De Gea etc, I know there's more but I can't think of them all right now. Then there's lads that weren't on big wages let go for small fees like Elanga and Gomes doing really well.
Sancho, Rashford, Malacia, Antony. They'll be another group that will be pretty much forgotten in a few years time and at Fenerbahce or Al-Alalalalal. Casemiro, Eriksen, Maguire, all of them will end up at some last pay day mid-tier club yet they're costing MU a million quid a week almost in wages.
It can't all be down to massive wage packets making them all lose enthusiasm/talent because United are definitely not the only club in Europe handing out fat contracts.
I can't speak for footballers as I've never been one, but I have worked in various industries in my 30 or so years as an adult, and all the places I've worked/managed that had a poor work ethic and lazy mentality all had the same thing in common. No fear of reprisal or loss of work. People basically knew they could put in 20% effort and nothing would ever come of it. New people would come in, work hard for a bit then realise (or get told) to forget it and just go through the motions.