There’s quite a few reasons, but I suspect the largest is lack of a corporate sponsor. People use what they know of, and few things have shipped with smalltalk.

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.

I'd generally agree with what you are saying... it was the tooling more than the language itself. That said, there was something to be said for the absolute simplicity of the language. With everything being an object that receives messages and the minimal syntax, you could teach people very quickly.

Why don't you just use it, rather than waiting for the industry to adopt it and translate it for you? The industry doesn't adopt things because they are great. It adopts things because it has to.

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.

I think people who say other languages "just don't get it right" are living in a fantasy world. At the end of the day, Smalltalk is a pretty extreme language. The insistence that, e.g., every integer value is an object that can be sent messages, or that every code block is an object, or that every code block can introspect its caller, all lead to a pretty extreme amount of flexibility but an inability to write efficient code or do much optimization.

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.

People unfamiliar with history live in a fantasy world.

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.

I'd say more of a dystopia than a fantasy world

I believe the Squeak/Pharo VMs are much faster than the Python and Ruby interpreters. There are other tricks - an Int maybe be an object, but a special one that fits in a register. The part that other languages don’t get is it’s the Smalltalk environment that makes it special, and there is just nothing like it in our modern tooling.

History is really important here. When Smalltalk systems first spun out of Xerox PARC, they carried hefty licensing fees. The whole free software / open-source movement wasn't as ingrained in developer culture back then. Worth remembering that SUN was marketing Java everywhere for free and that made a world of difference.