For many companies, it is deemed more valuable to quickly come up with a mediocre solution than to actually study the problem and engineer a good solution. Quickly assemble some libraries into a prototype that will go in production, then either get a promotion or change company. That is how I feel it works most of the time. Therefore developers don't really get/need to study how the system works: they won't be judged on how good they are in computer science, but rather on how fast they build the next prototype that will be shipped to customers.
Those who want to keep learning about actual computer science have to do it in their free time. Which is fine for a while, but at some point they grow older and have other priorities in their free time, which probably makes it look like they lose interest in CS.
I don't think it means that libraries replace computer scientists in making good software. Libraries enable developers to quickly assemble mediocre software, and they get paid for that. One still needs computer scientists to make good software, but most companies don't want that (because that is not what will increase their short-term profit).
Again, just my opinion :-).
Libraries take care of so much
Are these libraries written by magical code gnomes?
I studied computer engineering to learn to build stuff. Any theory I learn about today is mostly for interview prep.
I think folks get degrees in CS because university degrees are a path to a decent salary, and it’s a subject they like.
If your path is to write business software, a CS degree can be a good entry point but day to day work isn’t typically writing advanced CS stuff.
All analogies are bad, so here’s one comparing software to healthcare: a software engineer is more like your primary care doc (there are lots and they use proven solutions) and a CS PhD writing code for an OS on how to use CPU cores is more like a brain surgeon (there are few and they may have to find/create solutions).
the libraries lets me do more, it saves me time, it lets me avoid repeating and doing what other people can do better than me.
it opens me up to intersections of cs across other industries too.