It lowers the barrier to market for the end consumer product, but all of the stuff in between is gone. No more compiler vendors, or xml libraries, etc.
Is there some benefit to having compiler vendors or xml libraries guarded by paywalls? This is non-obvious to me. The days before the FSF and gcc were considered "dark ages" to programmers, being locked in to a small set of proprietary of compiler vendors and toolchains, fragmentation everywhere with poor portability and poor hardware compatibility. Yet you paint this as somehow a good thing and I'm struggling to see why.
I'm also still not seeing how the openness helps establish tech monopolies, which was the main point I took issue with.