If all bootcamps were closed down, would it make any difference at all to SWE employers?

I'll post some other time about how the bootcamp industry works, because it's an essay, novel, or feature-length documentary topic. This is a grossly oversimplified example, but hopefully gives you hope. So in the industry a really good senior engineer is worth about 10X a typical junior engineer in the value they deliver the company, but they are paid 2 to 3X in compensation. So companies really really want good senior engineers for a reliable bang for your buck. But the best senior engineers go to FAANG-level companies and make $500 to $1M+ a year in compensation. If you are a 2nd, 3rd tier company you can't afford that talent (who by the way is delivery 10X their salary still to their company, even at those high rates). What do you do? You need to hire entry level people for a lot cheaper and grow and train them (and cross your fingers) that they can make a junior engineer become a 10X "senior engineer". So you might hire 10 junior engineers at 1x cost each and 1 of them becomes a 10X senior engineer, who will be paid 3x cost. Maybe 7 of those other engineers will perform ok and break even and the other 2 are let go. After some time you are left with 8 engineers (7 junior 1 senior) delivering 17X impact for 10 unit cost. So the reason why there is a junior market is to try to identify the high potential junior engineers who can become senior engineers. And those people can come from any background and any walk of life, bootcamp, CS, etc...

Yeah, but maybe a caveat is that this is at bona-fide "tech" companies. Ask any eng manager and they'll tell you that internships and juniors are ,on average, net-negative financially, and the main goal is to turn them into super mid-level and senior engineers. This doesn't apply to non-"tech" companies (it does to some but not as strong), where you are expected to have a skillset coming in and then are deploying that skillset on day one, for example, agencies, contracting companies, tech-adjacent companies (like healthcare or financial companies).