Ubuntu Advantage is also free for personal use (for a few devices), so you can take advantage of that if you're not a business and are too lazy to update every couple of years.
Using an old distro with it's old shared libs and old compilers is definitely not for the normal home user ubuntu demographic that wants things to work easily. But for curmedgeons that hate change and can deal with editing some cmake/etc and source header lines here and there it's liberating. I'd like to use Debian more but 5 years just isn't enough.
There are also cases where modern versions of software are not better. Text to speech software is really important to me and Festival TTS modern versions (1.9 vs 2.0) just don't have good sounding voices. Luckily I still have my Ubuntu 10.04 box around to do that task.
Canonical keeping the base system stable and secure so I can build my source compiled userspace sand castles on top without constant (ie, every couple years) breakage is great.
If I had an Ubuntu desktop I'd pay for the first tier of Advantage since it's pretty cheap, but sadly their physical server pricing is too much for home use (225). Maybe they could make it 25 for the first server or two or offer a more crippled tier... dunno.
On the other hand...Proxmox.