The most successful and iconic basses, among them the J, the P, the Ric, the Stingray, the Höfner and many others have not changed their body shape because someone thought that after a couple of years of repeating the same thing, it's time for something new. They kept going because they were successful.
IMO Ibanez is one of those few companies that relentlessly comes out with new design ideas, not afraid to leave the trodden path and trying something new. Fender currently offers 4 models in total. P, J, Jag and Mustang.
Ibanez has 9 'standard' models plus several pro models that are not just an upgraded version of their standard line but something else entirely.