I feel proponents of any programming language put a lot of spin around what isolated aspects it is good for, but fail to illustrate what a programmer in even one target domain gains from using it.
Are there programming language implementations unlike what is described above, that you feel back up their marketing?
Counterexamples.
A simple language like Lua, whose advantages in actually building software rather than homework-level coding are well-documented, and borne out by well-received web servers, editor extensions, network software like Snabb (and Adobe something).
A platform language like Erlang that is not just simple to code in, but also has a mighty capable runtime. Demonstrating the value of that combination are the impressive networking and storage apps shipped with the platform, apart from actual software wins in the wild like ejabberd, Pleroma/Akkoma, etc.
An idea like Objective Smalltalk, which tackles software architecture head-on. https://objective.st/