You've got to be F-ing kidding me.
I've got a macbook pro retina 2012. I took the free upgrade from Lion (which came with it) to Mavericks... the NEXT POINT RELEASE.
It removed all third party drivers (even ones that were compatible with Mavericks). I was extremely lucky my USB 3.0 Ethernet hub had a driver on release day. Some I just installed right back on.
It removed command line tools breaking my build setup... and when I added that back I find there's no gdb with Mavericks. My build environment is crippled on lldb until the third party stuff can sort that out.
There's apparently been quite massive application platform changes, and a whole lot of software is now broken.
Apple quite obviously doesn't give half a shit about breaking anything that's not Apple software. That's the massive, space-elevator sized mindset fuckup that will keep them out of any significant share in corporate environments that actually need shit to not break any more often that absolutely necessary for... well... forever, until Apple gets the message.
Apparently, I was pretty spoiled growing up with Microsoft. Most third party stuff worked across updates... unless there was actually a real reason for it (driver level changes, etc). You know... because that's what USED to be purpose #1 of any operating system... be a platform to run crap reliably. Now, it's apparently be-the-ENTIRE-platform, and other software is apparently just a bunch of annoying freeloaders along for the ride.
The real tragedy is that this lazy mindset is infecting some Linux platforms (well, okay.. Ubuntu). They seem highly enthusiastic to duplicate Apple's boneheaded modus operandi.