A large majority of people you’re chiding for not learning from others, don’t even realize those other things exist.
The car industry probably wouldn't be as big, if you had to learn a new tool for every new car.
The reason this is a problem is because web tech is constantly changing, to the point that so many of these projects end up in the scrap heap far faster than other tech. It causes problems with long term service due to compatibility issues with ever changing dependencies.
And sometimes it’s just resume building or intellectual curiosity itching.