Personally, I love single cut designs, so much so now that I actually find non single cuts a little funny looking
As mentioned above by a few folks, the extended shape comes from accommodating the additional scale length you get with a bass, when compared to a Les Paul or a Tele.
All of that is moot is you play seated of course, but on a strap it REALLY matters, especially for us shorter bassists.
You can get single cut basses, with more guitar proportioned bodies, Gibson make, or made a Les Paul bass for a while, with a marginally oversized Les Paull guitar shape, but it didn't sell well at all, like most Gibson basses sadly. I think in part that flopped due to the neck dive and extended reach for first position.
Ultimately, I think single cut basses, esepcially modern style ones will forever be THE martime of the bass world.
I love them, but oddly I hate martmite...
The offset thing, the original marketing for the Jazz Bass noted that it was "offset" as one of the main USPs, so I have no idea why Fender seem to omit it from their more recent offset marketing strategy...
Eude