Rocket scientists are not exactly a dime a dozen. Yet, now we have rockets and launches coming from everywhere. SpaceX, Virgin Galactic, Jeff Bezos, NASA. Where are these people coming from ?
Almost every engineering school in the country has an Aerospace Engineering department, and "rocket science" is very much on the curriculum in those departments, because there historically has been a lot of demand from the big, established defense firms whose main business is building missiles. Most of NASA's current active crop of launch vehicles started out life as ICBMs. This means that there ARE engineers out there, and more graduating every year, and SOME of them aren't satisfied with shuffling paper ad infinitum: they by golly want to FLY something!
There have been quite a few startups in the field, guys who had interesting ideas and couldn't pursue them at NASA or the established companies. SpaceX, Virgin Galactic, and Armadillo Aerospace (Carmack's company) all have independent, committed funding, from their respective founders, who are determined to make it all happen REGARDLESS of what NASA thinks.
AND...
There are a lot of model rocket people out there, adults AND children, and some of them never lose the itch. A fair number of them graduate from Estes/Centuri black powder engines to the much bigger Tripoli rockets, which use the real-life APCP composite propellant, and lack only a guidance system and warhead to make them the equivalent of the smaller missiles currently in the defense inventory.
In short, like the Truth, the People are Out There. This particular genie is out of the bottle, and he ain't going back in without one hell of a fight.