Because in the not too far future the Linux community will largely run away from 2.4? In fact the motivation of many developers to continue with 2.4 is quite down already and Marcelo is going to put 2.4 into deep freeze after 2.4.25.
As someone that does _product_ development, 2.4 is going to be used for a long time. It may not be interesting to people with the goal of software modification, but when you are deploying real devices to real customers, people finding bugs is the last thing you want to see.
-- Dan
