I started my Web Dev career in 2005, around the time "Web 2.0" started to pickup steam. It was (In my recollection) really the beginning of the Web Application

I started my Web Dev career in 2005, around the time "Web 2.0" started to pickup steam. It was (In my recollection) really the beginning of the Web Application model. Users were starting to expect web pages to do more, and be more than "click a link, go to another page" I'm certain any developer from that era has a story about writing tools to make their own life easier. Prototype and jQuery were popular as they abstracted a lot of the obnoxious stuff you had to do over and over again. And the story goes on from there. The complexity is a story of trying to simplify for the developer, and then trying fix the costs of the overhead from those simplifications. As for your second question. It's not necessary of course, but if you don't use these frameworks and tools, sooner or later (I think) you're going to be engineering a solution yourself.