Team of the year (both according to Kicker and the players player award) in Bundesliga at the age of 23 in his first season. Very highly rated by a majority of the Bayern fans I know and it seems to be the same online.
I guess great is relative. But by that standard I’m not sure I think Rashford fit that bill either. And I also think CBs peak later than attackers.
Let's start on what unite the three. All of them are of similar age (22-24), they were considered as generational talent and are not wanted by their respective clubs.
De Ligt was immense at Ajax. He failed at Juventus (to the point that they started calling him goalkeeper because of him handballing the ball in 4 consecutive games) and is now surplus to requirement at Bayern. He's got a 250k a week salary and there are question marks about his fitness as well as his ability to play at a top club level.
Sancho was consistently good in a league that is way more tougher then the Eredivisie. His stats with Dortmund (first stint) were near Messi esque. He tanked in the EPL and he wasn't as good during his second stint in Germany. However he still did enough to be wanted by Dortmund (though not enough for them to pay 40m + his salary). Unlike De Ligt whose issue seem to be around whether he's good enough at top level + injuries, Sancho's issues are mostly about attitude. Whether one is worse then the other is open to some serious debate. Some say that availability is the best attribute while others say availability is key.
Greenwood's issue is well known. I don't want to debate it at all. All I would say is that he shouldn't stay at United and that a big chunk of foreign based clubs don't give a feck about it. On the pitch Greenwood has a way better track record then both of them (he succeeded wherever he played), he's the youngest of the lot and unlike Sancho/De Ligt he's on a reasonable salary (75k) which makes him quite attractive transfer wise.
I can add other players who were in similar situation including Maguire (older but on a huge salary and was considered not good enough for United) and Sanchez (older, on a huge salary but was considered not good enough for United)
Players in such scenario are often sold on the cheap (usually with a chunk of their salary still paid by the seller), given on free or sent on loan usually with some of their salary subsidized.
United as a whole has a tendency to underrate their own guys while overrating players from other clubs. Case in point were Nicky Butt, John Oshea, Jonny Evans and Phil Nev (all sold for peanuts) as opposed to the likes of Sanchez (good track record but already showing signs of decline), Bastian (a relic) and Casemiro (still good enough but was transitioning to a squad player status a Real). That needs to change. There aren't many (if any) clubs who are willing to bid good money for a highly paid player whose struggling at another club. It's time we leave that exclusive group of morons