IMHO, simply, the album is older (so any cut from it is "deep"), they don't believe the songs work well live (which is probably why Loneliness was dropped almost immediately), the album wasn't that big of a hit, it has a production and a certain style that dates it somewhat, the album is a bit more on the wanking side, at least for Maiden (I'm listening to CSIT as I'm writing this)... Easily, I don't think the band (and the general Maiden public) think of the album as highly and as often as we here do. Way too much a... eh, "cult one" for that.
EDIT: Not to underrate them, of course, but I have my doubts about how well would they be able to play the intro/verse to SoM nowadays, or Loneliness, or that weird part in AtG. And CSIT... I would love it, totally, absolutely, morbidly, but I just don't see the crowd cheering for it that heavily. Wasted we got and HCW is the one I definitely could live without.
Deja-vu is way too much of a deep cut, even in the context of this album. That would be totally out of the left field.