You can, especially if traveling to a region where it’s endemic and common. I got the series at a Kaiser travel clinic just by asking when I was planning out a long international trip. You still need post-exposure shots, though fewer (and maybe no immune globulin, if I remember correctly).
The rabies vaccine needs fairly frequent renewal (more than once a year). People likely to contract it (vets, pest control, zookeepers, etc) get them. Others get post exposure treatment that is very effective.
People who work with bats or are otherwise at risk of coming in contact with rabies are actually getting the vaccination like they get others (note: in Germany).
I bet you could make a lot of money advertizing an elective rabies vaccine to people searching for rabies on YouTube. They might not ultimately need it, but if they're willing to pony up some money for peace of mind, why not?