I think this is not a useful or productive mindset. I mean the idea of "I spend hundreds of hours learning $TECH in order to get a job in it".

If you learn it because it is interesting to you and you enjoy the process of learning and using the language/tech, then that's all good. How to "monetize" your hobby is a separate question that should not factor in whether you should or should not cultivate it. There are probably many ways to monetize it. Landing a job is just one way.