Hope I'm doing this reply correctly.
Blue, perhaps "hurt" is a tough concept to deal with, since their albums were so near perfect. But think about having the singles on the albums. What album wouldn't be helped by She Loves You, I Want to Hold Your Hand, etc.? We Can Work It Out? Day Tripper? Keeping those off albums was part of the times -- I'm not arguing that -- but their inclusion helps any album.
My point was, Pepper, cultural landmark that it is, could have been better by adding Penny Lane and SFF. I'm sorry, but that's a fact. Someone else can tell you which albums the singles would have gone on, because I don't have the encyclopedic knowledge of recording sessions/release dates.
But reverse engineer it, for a sec. Imagine a White Album with Hey Jude, Lady Madonna and Revolution, and make the argument that it would've been better with #9. Good luck.
I didn't read every post in this thread, but I think I understand the case you're making.
I don't think there is a steadfast rule about it... sometimes adding the songs would "help", sometimes it would "hurt". So what do I mean by this?
Well, the flow of an album is sometimes as important as the individual songs it contains, and the inclusion of a (great) song (that might have been a huge hit) that breaks this flow may in fact leave you with an album that is significantly "inferior" to what it was. A White Album with Hey Jude, Lady Madonna and Revolution might work, but adding Penny Lane and SFF to Sgt Pepper might not, because that album is greater than the sum of it's parts precisely because of how it flows.
Adding Helen Wheels to Band On The Run worked, and fortunately did not disrupt the flow of the album. But the US album Hey Jude was just a bunch of singles and b-sides had no flow at all. The Ballad of John and Yoko might have ruined Abbey Road or Let It Be. But I like the flow of "Let It Be Naked" better than the original with the inclusion of "Don't Let Me Down" (which should have been on the original Let It Be).
It's hard to say. If adding the single doesn't break the flow of the album, but enhances it or at least maintains it, it's certainly better to have the popular songs on there. I couldn't imagine Band on the Run without Helen Wheels, or MMT without PL and SFF.
I am intrigued by a White Album with Hey Jude, Lady Madonna and Revolution and without Revolution #9 though....