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 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.
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.