like I feel like there are now a lot of people who are knowledgeable of everything but master of nothing

In general that is not necessarily bad, it can be a good thing.

they keep learning framework and library without caring about software principle, architectural or design patterns or security best practice

My guess here is that it is a way to get into more interviews. Many job openings today lists a ton of libraries and frameworks that you should have experience with, thus the market reacts(!) accordingly.