Why ?

this is not exactly correct: the automotive industry does try NOT to reduce the use of vehicles that use mineral fuel and this is because they have invested in conventional assembly lines they want to use as much as possible.

indeed, there is push on the other side to reduce their usage (by some organisations and society generally speaking). the reasons are 2:

1. to reduce pollution and thus to preserve the environment
2. there are strategic minds that understand that the mineral fuels will end at a point and that we need a smooth transition to other ways of generating movement so as to avoid a disastrous crash of the world economy when they will actually exhaust.