Daniel Suarez [1] has written a book where he imagined how this could happen (Delta-v)

[1]: https://en.wikipedia.org/wiki/Daniel_Suarez_(author)

P.S. Read a lot of his book, great author

> if we really want a presence off of earth we'd be better off building larger and larger space habitats and bootstrapping a mining industry in space

This turns entirely on how human biology works in zero versus low gravity. (Same for spin versus natural, or linear, gravity.)

The experiments we need to be doing is building and launching space stations and planetary bases for mice.

Agreed. Once it becomes commercially viable to start building things in space, it'll take off on its own. There will be constant pressure to build faster, safer, more capable craft. Whether that will lead to something like FTL isn't possible to know, but at the very least it's a step towards a space-faring civilization.

Yep, so long as there are clear, positive incentives or it could become a corrupt, expensive boondoggle depriving ordinary people on Earth. And Mars ain't it except underground.

Nit: "earth" is dirt, but "Earth" is always capitalized when referring to the celestial body we inhabit.