You started out saying, "systems that were once free become in practice proprietary and unfree even though there is some free almost worthless version hanging out under the BSD license". Yet it served Linux fine for over 20 years, while most of the commercial Unix's died out. Your point is invalid.
Are you that dishonest or just stupid? X Windows is invented in 1984. X11 comes out in 1987 and at that point commercial Xs are viable and introducing all sorts of cool features many of which are still not in XFree86. XFree86 starts in 1991 because the BSD licensed version of X is worthless. Linuxes are using commercial Xs mostly. XFree86 doesn't become really usable until 1995 or 1996 and even then it is just providing the basics still well behind the commercial X's. Your 20 year time period starts with an XFree86 that is nowhere near what SUN or SGI have and by then the the UNIX workstation market is on the decline. Linux misses the conversion and that instead goes to Windows NT. And the reason for that failure of X is the BSD license allowing commercial Xs not to share back. It isn't until the early 2000s that Linuxs have caught up with where the commercial UNIXes were in the early 1990s. The BSD version of X11 didn't serve Linux it crippled it.
Stop posting stupidity. Deal with the reality of the world. And if you don't know it, look it up.
You seem to think because a proprietary fork exists that counts as a failure.
No a proprietary fork that becomes the norm is a failure. That's the definition. That's what you are debating that BSD protects free software and keeps it free.
As for Apache if the value adds on top of Apache are proprietary than Apache is not thriving.