Why is the life of Ubuntu 13.04 so short?
Canonical switched to a 9 month support plan for non LTS releases because back-porting bugs and package upgrades was consuming too much time for the company, since most users of non-LTS releases upgrade each cycle.
Source: Too much time wasted reading about Linux.
After further browsing, I found this :
Ubuntu 13.04 will only be supported for 9 months. Previous non-LTS releases were supported for 18 months. For more information, please read the announcements here or here.
The first link tells :
The rationale here is that it’s costing a lot of time to maintain all those releases for 18 months. It’s also causing a lot of load on the SRU team and on developers to ensure that upgrading from one release to the other won’t cause regressions due to fixes being SRUed only to a few releases.