I would agree that modern vehicles can require greater power demands. Both my recent cars have lithium ion batteries due to increased power demands over traditional 12V. And other cars from other brands are doing similar things.
In my sports car, it's just the one LiPo battery with some amount greater than 12V (I can't remember the exact numbers 'cause, well, it's irrelevant and uninteresting to me). In the SUV, there's both a traditional a 12V lead-acid one, plus a LiPo one (lending some support for your argument about existing supplier relationships, in other words, including the lead-acid one was almost certainly done for cost saving reasons rather than engineering reasons, and the lead-acid one will almost certainly be phased out in subsequent model refreshes).
However, electrification existed before Tesla existed. And minimalist interiors are not any kind of a feature; they're a cost saving measure being marketed to easily fooled idiots as a feature.
And what is this "software based UI" to which you refer?

Software has had software based UI since the very first human-interactive computer program was written. Where'd you get the idea that Tesla is someone inventing that or inventing anything related to it?
FInally, there's nothing magical about the choice of 48V. Modern cars might need more than 12V at times, but they don't all need 48V and there's no great reason for it in most cars. Trying to claim a specific voltage is some sort of brilliant breakthrough by Tesla is pretty ridiculous. Step back from the abyss man, you're being brainwashed by Tesla marketing into saying silly nonsense.