[antjanus]

I definitely agree with you on this point. A lot of the "new stuff" is just a rehash of the old or a new implementation in a different language of something that's been around for forever.

I'd say the front-end MV* stuff is a great example of this. I started out with KnockoutJS a few years ago and that's all but dead by now. Was it a waste? No, not really. It was pretty easy to go from Knockout into Angular. Sure, some concepts are different, but the ideas are the same. Moving on from that, I picked up VueJS pretty quickly and after tinkering with its Component-based example, I saw that it's pretty much almost the same as Polymer. BAM! All of these frameworks wrapped up in a nice package.

And what's behind it all? An idea. The concepts behind all of these are the same. Same goes for working with PHP vs Ruby, same concepts, different syntax, slightly different ecosystem. NodeJS (as much as I love to say how amazing and different it is), is pretty much the same as Ruby and PHP and Python except for its damned callbacks.

And then there are things like underscore (which is pretty much an array manipulation library), and backbone (which is just a library that gives you the MVC of javascript) etc.

All of it old concepts, and all of the similar libraries work very similarly. There's no need to relearn everything from scratch once you get the patterns and concepts down.