They're blowing up their own money, unless you still count it as being the taxpayer's after the government pays them for launch services.
But that still means it’s not just taxpayer money, it’s mostly theirs. They’ve been raising equity rounds this whole time.
Without Spacex, the typical cohort of gov contractors would have been happy bleeding NASA dry with one time use rockets that have 10x the launch cost and carry 1/4 the cargo.
Isn’t SpaceX the largest launch provider in the world and for the U.S. government?
Many times than the rest of the U.S. space industry combined.
Falcon 9 has had plenty of "ROI" but it wasn't really federally funded. Let's not get carried away though about "more than the entire US space industry combined," though.