The creator/head developer of litecoin wanted/supported it, that's why it was implemented immediately. Whereas on bitcoin, since it was more decentralized, the community was split into 2 groups. hardforkers and softforkers. They have been debating for months, hence there was no real progress. Gotta watch out for August 1 though, UASF is makin a move. As of now we don't know what's gonna happen though. Maybe a chain-split.