In fact, I'd venture to say that one of the main reasons Smalltalk isn't used more is the repository.
That's been my impression as well. SmallTalk always sounded like a killer system back in the 1990s when I first started getting peripherally exposed to these things. But it was a turtle on reasonable PCs. IBM had a SmallTalk push for a while, but few took it seriously. Horror stories of corrupted repositories didn't help.
So its chance to have a big slice of the pie never really came. PCs that were powerful enough and cheap enough didn't arrive in time to prevent things like C++ and Java from grabbing all the interest.
If SmallTalk were able to make intelligent use of the network to grab objects as needed, so that one wouldn't need a 25 MB image file to make a, say, 500 kB application, then maybe it could have a phoenix-like rebirth.
(Yes, the above is ramblings from someone who hasn't used SmallTalk for more than a few minutes in playing with a demo version of a ST or two and who really doesn't know that much about it. But that hasn't stopped me, or many of us, from commenting before, has it?)
Cheers,
Scott.