Unless the feds can take California out of the regulatory picture, I don't expect major steps backward. Almost half the country adopts California's emissions standards.
They might be happy that they can keep making V8s, but they have to know any future administration could easily outlaw any design that goes too far backwards. Such a car will also not be able to be sold anywhere else in the world. Heck, by the time they design, tool, and produce such a beast it could already be too late.
The demand for EVs is crashing across the board. Porsche for example is now in dire straits because they had promised to make the 718 only as EV and with demand going down, they'll revamp the platform and get ICE 718s back.