I think United, as a whole, are really overrated as a European force. We're just not, and we rarely have been.
Some of it comes down to timing. If we'd been the dominant force in the 70's/80's, when the league champions won the European Cup pretty much every season, then we'd have more CLs then we do. By the same token, we started our own period of dominance when we weren't even allowed to enter European competition and it took years to bridge that gap. And we also had the misfortune to continually run into that incredible Barcelona team.
So we've been a bit unlucky too. But as a club, we just don't have that affinity for it that you see with some clubs. We have to be miles better than the majority of the competition to even stand a chance of winning it. And even then we usually mess it up.
Liverpool and Chelsea have won the CL whilst finishing fifth and sixth in the league. Can you imagine a United team ever punching miles above their weight like that? Not a chance. Doesn't happen, ever.
Liverpool always seem to be competitive in the CL, even if they're third or fourth in the league. Then there's Real Madrid.
We're not even competent in the Europa League. We should've won that a few times, or at least got to the final and competed to win it, but we fail constantly.
We're just not good at European football. We're just not. It never feels like a natural fit somehow.