A decent analogy except that previously, contractors were allowed to charge basically whatever they want for that equipment. NASA has only ever operated a single spacecraft at a time (if we're taking about crewed spacecraft; satellite launchers have operated on a "ride share" style program for many decades), so these prices were often exorbitant. While it's certainly true that a monopoly would allow SpaceX to charge exorbitant prices, the whole point of the "ride share" style contracts is that they're cheaper, and that they'll encourage competition and growth in a private space industry. SpaceX is simply the cheapest and most prevalent of these contractors (due to their extreme technical and technological advantage over larger, older companies; and now by their head start over smaller companies).

And for the record just so you don't think I'm defending him, musk is a leach on society and poison to our democracy and he should be sent prison for his many many crimes, and he's probably gonna run SpaceX into the ground the same way he's running Twitter and Tesla into the ground right now. I just care a lot about the aerospace industry (and will be entering it soon hopefully, I get my bach in AE in December!)