
It took them 3 years (11.04 -> 14.04) to make unity really good, and now it is EOL since next version will already switch to unity-next. Old an new share almost no code in common under the hood so to me the first gen unity (versions 0-7) seem a bit like a wasted effort.
On the other hand this is going to be one of the most used if not the most used Linux OS for the next five years, so perhaps it is a dignified death to the codebase.