We are on Ada 202x nowadays being discussed, and in a world where FOSS tool makers have problems making a sustainable business, always changing licenses, there are still 7 Ada vendors selling compilers.
In embedded world restrictions on the output is the last thing of worries while fulfilling various certification requirements can be a big and costly headache.
And from the vendor point of view releasing a compiler under libre license allows for concurrents to undercut one on R&D leading to the compiler and related tools certification. So from business point of view it just makes no sense. This is very different from contributing to, say, clang, where a cost of maintaining own closed fork outweighs any disadvantages of contributing.
