Predicates are great but most of the good stuff including privacy, proper subtyping and abstract data types came with Ada 83. Rust can't hold a candle even to Ada 83 imo.
Ada has practically no mindshare, Rust does. Just like say, Scala, things can be technically 'good', but without adoption it isn't going to get the attention and visibility to compete with everything that does.
We're talking about mindshare, not commercial incentives. There are plenty of things sold to small groups of buyers with no significant mindshare. Mindshare does not equal commercial viability or sales numbers.
As for who would pay for a Rust compiler: probably not a whole lot of people unless that compiler has something special the offer that the normal compiler does not.
The same goes for a C compiler, there are Intel compilers that are supposed to be 'better', but as it turns out, in most cases not 'better' enough for people to pay for them. But even then, I would not be surprised if more people pay for the ICC than for Ada (but I would also not be surprised if the Ada compiler sales rack up more money than the ICC sales).