Just because there is no developer preview version of Android L for the Nexus 4, doesn't mean that those with the device should pack it in after Android 4.4.4.
This information was discovered on the code.google.com website and includes emails from two different Google employees, both revealing that they are using the Nexus 4 with the "LRW52G" build of Android. For comparison purposes, Android L on the Nexus 5 is build "LRW66E."
Why wouldn't Google want to make the Nexus 4 support Android L? After all, the entry-level Android One handsets will run Android L and the Nexus 4 is higher spec'd.