Given how much memory and CPU time is burned compiling Rust projects I'm guessing it is pretty complex.
I'm not deep enough into the Rust ecosystem to have solid opinions on the rest of that, but I know from the specification alone that it has a lot of work to do every time you execute rustc. I would hope that the strict implementation would reduce the number of edge cases the compiler has to deal with, but the sheer volume of the specification works against efforts to simplify.
> They could also have funded developing a free, open source toolchain.
If the actual purpose of the Ada mandate was cartel-making for companies selling Ada products, that would have been counter-productive to their goals.
Not that compiler vendors making money is a bad thing, compiler development needs to be funded somehow. Funding for language development is also a topic. There was a presentation by the maker of Elm about how programming language development is funded [0].
Possibly, I am not sure, though Delphi, a successor language, doesn't seem to advertise itself as having pattern matching.
Maybe it is too primitive to be considered proper pattern matching, as pattern matching is known these days. Pattern matching has actually evolved quite a bit over the decades.
1: If you had to guess, how high is the level of complexity of rustc?
2: How do you think gccrs will fare?
3: Do you like or dislike the Rust specification that originated from Ferrocene?
4: Is it important for a systems language to have more than one full compiler for it?