(And now in the age of LLMs, the barriers to get started with a new programming language are lower than ever)
Additionally, anyone who has seen how Swift evolved should be wary of Lattner saying "the language is mostly stable", or even "the language is released".
Nvidia is also a major contributor to MLIR, which they use for TileIR and ClangIR, so should a compatibility break occur it wouldn't be entirely up to Mojo to fix it.