People end up choosing something that has batteries included so they can focus on solving business problems. A programmer who will superficially understand SpringBoot without understanding how it works. Really, there is no magic there - its a few core concepts - annotations, bytecode enhancement and dynamic proxies. Maybe Im missing one or two. Everything else is built on top of this.
This is regardless of language/ecosystem. If I do not understand the fundamental concepts, I will never be successful in that ecosystem.
But that's like saying that a bicycle is better than a car, because the first is simpler to understand. (At the same time, nothing prevents you from assembling a bicycle in Java if that's indeed what you need. But for general long distance travel you are better off starting with a car frame, aren't you?)