A large amount of programmers are hired just building crud apps. Display data from a database and write it back with a validation. Etc.

There is very little innovation going on. And most companies do everything they can to stick to standard patterns, technologies etc where all the risk is removed and known in advance.

Often "good" programmers are worse - they over complicate the architecture, go off on tangents, try to solve problems the business didn't ask for either etc.

So bootcamps filled a need.