Plus even being "defensive minded", that doesn't mean you don't have defensive flaws too. Or that there aren't some styles of defending that translate better to a top side than others.
In Palace's compact Hodgson system AWB simply had less space that he had to defend, which reduces the chances of poor positioning being exposed. Whereas in a more expansive side that side of the game becomes more important, just as ability on the ball does. Palace weren't a side like Brighton who play in a more expansive way, so there had to be a greater need for an extrapolation and projection of his skillset to a different style of play.
And as another piece I read pointed out, even AWB's strengths should have prompted their own questions. He's unquestionably excellent at tackling, but those stats should also have given cause to ask why he was posting an extremely high tackle count (99th percentile for tackles made) despite having a relatively hard-working winger in front of him sharing the defensive load. It's not like the other Palace players were making similar amounts, so did this point to some issue with positioning on AWB's part? Or (much more likely) a tendency on AWB's part to actively invite wingers on to him because he knew tackling was his main defensive weapon, a strategy which becomes less viable when you're playing in an expansive side. And sure enough, we've seen the amount of tackles AWB makes per 90min decrease with each season he's been here. And if sheer tackling ability was going to be rendered less important at a top side, what was he offering that made him a 50m fullback?
Exactly this. People get carried away by defenders that play in a defensive team, then they are exposed when they make the step up.
AWB in that team was defending deep, everyone always remembers the 10 tackles made but by doing that it allows you to make 1/2 errors and get away with it because of the pressure they come under.
When a defender has to make slide tackles and that is his primary trait, however good you are, it is a risk, you are bound to mistime a few which will mean fouls, penalties conceded. Look at Varane for instance, he doesn't need to slide or tackle, positions himself in a way that no one notices him, cleans up.
When a player has to do so much defending and has 2 DM's and RW covering back, its easy, the step up to United when the game is open, you are left one v one its a different ball game.
I have seen him on numerous occasions push to try win a ball back gets nowhere near then jogs back? It really frustrates me, as a defender you need to sprint back into position.
I wouldn't say we got sold a dream or anything, I put it down to negligence from our club in not scouting the player properly before buying.