Forking everything to lock APIs at a given level discards the advantages of rapid, open development happening upstream. Maemo has wandered partially down that path several times already--with GTK, with being "Debian-based", etc.--and the going has always grown rapidly tougher as distance from the beaten path increased. As nice as it is to let users keep old applications from vendors long gone, binary compatibility leads to nightmares like Haiku's hybrid gcc2/gcc4 system.