Take Javascript, for example. It's the top language on Github. Its not there because its everyone's favorite language, or because it's an ideal language for writing reliable software. Its there because its baked into web browsers. We're now starting to get full-featured reliable compilers into JS with sourcemaps and whatnot, plus things like webassembly. So it's becoming quite reasonable these days to write code for the web in a language that isn't JS and not feel like a second-tier citizen. But that hasn't always been the case, so people wrote a lot of JS out of necessity. And that's why it's at the top.
(I don't mean to riff on JS in this post. There are plenty of other opportunities for that. The language has improved over the years, and this is surely part of the reason it's remained at #1, and part of the reason why browser vendors didn't throw up their hands and try a different language instead. But the main reason its at the top is because it's the language of the web.)
If SmallTalk were built into browsers instead of JS, then we'd all be writing SmallTalk. And it'd be blazing fast. And that has nothing to do with how sound its design is.