There's probably that, too.
I have to confess that I bought a lot of the early VHS compilation tapes (Best of DS 1 & 2, Best of Barnabas, Scariest Moments, and especially the 1840 Flashback) - but that was because 1) they contained material that hadn't been seen since it was originally broadcast, 2) with only 20 eps coming out monthly on VHS, it was still going to be years before that material came out on the regular VHS releases, and 3) there was really no guarantee that MPI was even going to continue to issue VHS releases long enough for that material to actually come out. The notion of all of DS coming out on VHS was certainly a dream we all hoped for, but it was far from a certainty, especially considering how impossible it seemed to be to get the fifth year of the show out in syndication - and releasing the pre-Barn era seemed even more impossible. Thank heavens everything did actually come out! But that's just the thing - now that everything is out, unless you're a completist, the compilation DVDs often seem superfluous to the average fan, so I can't imagine that they sell anywhere near as well as the VHS compilations once did. And so this new DVD collection probably will be bought mostly by impulse buyers who might not be willing to invest in a more expensive collection, in which case, calling it a "Collector's Edition" would seem to come across as a misnomer...