I know what you guys are saying and I agree to a point, since I bought all 8 volumes, most on their day of release.
The Movies Unlimited write-up begins "Along with volumes 1-8," which might mean the eight volumes will be included "as is," and maybe the rest will make up a separate release or two. Maybe they will issue the extras as a separate set. (But I'm not going to hold my breath -- as others have pointed out, Sony is not known for doing that.) But part of me is saying if they really wanted to "stick it to" the hardcore fans with a big "cash grab," they would have included all of the 1960s features as well. (Maybe even those colorized shorts too, why not?) I note that NONE of these extras have been on DVD before. And apart from Have Rocket, Will Travel, the rest might not have even been officially released on VHS either -- not certain whether these particular cartoons were on video or not, but that's definitely true of all the solo shorts.
Bottom line is that a lot of stuff is coming out which a lot of us have wanted for years, even decades. (I'm talking Stooge fans here, otherwise this stuff isn't even on most people's radar.) And that's definitely a good thing! I would love to have all those solo shorts from clean sources, without multi-generation tape artifacts and sans superimposed foreign-language subtitles. I say bring it on! (That's assuming they have pristine source material in their archives, and I've learned never to assume that! But I bet they do...they have to have better stuff than what's out there now!)