At the end of the day, languages that were less extreme won the popularity contest. Ruby and Python, for example, are just more accessible and full-featured.
Smalltalk or more specifically one of it's dialects, Self (an even more "extreme" Smalltalk), made huge advances in JIT compilation. Advances which later ended up in the Java HotSpot virtual machine. Some benchmarks hit half the performance of optimized C. That was in the late 90s.
And honestly, the language itself isn’t that remarkable by today’s standards; there’s so many dialects floating around most of the features have made their way into mainstream languages. It’s the tooling that I dream of. Sadly, it’s probably also another reason why it never took off: people couldn’t easily incrementally adopt it.
In my little corner of the industry, we've adopted a big heap of things for entirely political reasons, and they're mostly crap in one way or another.