While I don't see that mentioned very often I do think off-Earth settlements could have many benefits even for the Earth population - say research commoning from experience of living in space environments could have application on Earth. Also many asteroid strikes could be much more likely to be detected and averted using in-space instruments and infrastructure.
Even more exotic stuff like dropping first responders from orbit to disaster areas might be useful, but would not ever be doable without infrastructure in place for supporting space operations.
I kinda agree that most humans won't leave Earth, at least for the foreseeable future, even if those things were magically built this year: even in 2019, international tourism was only 1.466 billion people, less than 20%.