@ngn re Dyalog "resting on their laurels forever": I'm sorry, but this is an absurd statement. Dyalog APL has a larger full-time development team, and is consistently evolving faster, than ANY APL system in the history of the language. We added dfns, OO, real Unicode support, DotNet integration, see https://www.dyalog.com/dyalog/index.htm
These advances would appear to be the main cause of your so-called "vendor lock in".