Bdp,
I'm basically a cult band guy, too. Richard Thompson, Los Lobos, Feelies, Bongos, Matthew Sweet, Kid Creole, Rebirth Brass Band, James Booker, Don Dixon/Marti Jones, etc, etc. Some have had their brief moments on the charts, but as a whole, this isn't a big-time record selling crowd.
However, Todd Rundgren has sold a ton of record and he's an A-list guy for me. My absolute favorite band is Fleetwood Mac and they have sold a billion records. So, I'm familiar with the conundrum you mention.
In my book, ABBA is great fun. I just took my wife and 10 year old daughter to see Mama Mia and we all loved the music. These songs may not break a lot of new ground, but they are absolute brain worms. I'd call it pop music within a rock n roll rhythmic scheme rather than straight-up rock n roll, but I'd say the same thing about The Beatles' music.
BTW, that's not some kind of veiled criticism of The Beatles (whom I regard as pop masters of the highest order). It's more a function of how I have heard the art form evolve over time vs how others have heard it's evolution. In a sense, anyone who is inclined to make sub-genre distinctions within the broader range of pop (or rock or country or funk, etc) music of the last 50ish years, does so by listening in inverse chronological order and seeing patterns. However, the significance of those patterns will differ to each of us.
You mentioned your narrow definition of "pure" rock n roll in an earlier post and I have mine, too. It's a bit different than yours, but - in the end - neither matters too much. Pop music genres cross-breed with each other. The results can be parsed in a bunch of different (but still valid) ways. I have a particular love for my brand of "pure" rock n roll (the songs of Chuck Berry would be a good short-hand definition), but I'll consume pretty much any music that works on its own terms.
I continue to enjoy your posts and the interesting take on this subject.
Marty
Note Bene: Have you ever heard the ABBA live album? It's a two record set that includes a rocked-up version of "Gimme, Gimme, Gimme" that's a must hear for rocking' ABBA fans.
