Not a bootcamper but I think this isn't true. If you put in the effort and you're moderately intelligent you can speedrun pretty much any career in terms of knowledge.

However I do think there's a negative selection bias in the people that end up doing the bootcamps. They're not the self taught people that can teach themselves x in a few weeks. These people don't go to bootcamps, because they already taught themselves x and don't see the purpose in doing a bootcamp for a lot of money that teaches them x and doesn't give them a useful certificate.

The main benefit I see in the classical university track is that you gain more breadth of knowledge. And while you may not need most of it, it often helps in problem solving to know that some things "exist". Just so you can Google the details when you're faced with a similar problem.

The other benefit is of course the signaling value. Bootcamps don't have much of it.