You are deluding yourself if you think open source folks are better. You can't compile and run a modern version of GCC on Solaris 10 on SPARC, for example. And we just had a story here last week about removal of bus mouse support. It's only a mild exaggeration to say that lots of folks will check the commit activity on github and of a project doesn't have commits this week it should be banned from the internet and the universe.
Then you have the problem that many dev tools are not forward compatible. CMake is a huge issue. An ubuntu system from 2020 has CMake on it, but it won't compile anything that uses CMake that was released in recent years because the cmakefiles are incompatible.
Bus mouse support isn't removed because it's old but because it's been broken since 2015 and nobody noticed.