The Alvin Show was only on for one season, so they could easily release that into a complete series set; heck, for the longest time, there were rumors that a complete series set for that show was going to happen... what does this set contain? The pilot episode and what? Two other TV specials as bonus episodes and that's it? It ain't worth it.
I wish I knew exactly which songs in specific that were featured on the 80s show that they can't use, because with all that's been released on DVD so far, I've only found TWO episodes that have song replacements - one where a really crappy dub of "Witch Doctor" was dubbed for "Love Potion No. 9", and where "Surfin' Safari" was dubbed for "Surfin' USA" (ironically, both are Beach Boys songs).
They are getting "better" at the DVDs though - so many fans have been complaining about lack of title cards (which were removed in syndication anyway), but as of late, more episodes on DVD have kept the title cards intact; all episodes on The Chipettes DVD have them.