>>1987What you have to understand is that since 2009 or so with Googles invention of the V8 javascript engine, execution of javascript has become way faster on the front end, leading to frameworks like angular etc. This is attractive to employers because
1) it pushes all the computation of rendering and re-rending the UI/view onto the user's computer/phone, not the server as with traditional server side rendering. This reduces costs especially in cloud environments where you pay for that extra compute time (ex: amazon web services).
2) It's faster to make certain kinds of apps that have a lot of user interactions (i.e. web "apps" like twitter). Traditional websites don't really benefit much.
3) From a hiring perspective, front end only dev is a lot more accessible intro to development than traditional back end dev which is traditionally the domain of CS majors and enterprise devs. Now you can use those back end devs for the database logic and APIs, while letting some non degreed hipster graphic designer learn react from a bootcamp and still make a pretty good UI, since most of the scaling will be on the backend anyway, performance isn't usually as much of a problem on the front end unless you're doing something really wrong.
4) Hype. Theres a huge hype around SPAs right now.
5) It simplified the backend. Now that you take out the presentation layer out of the backend, there is no need for complicated templating systems, xml, html, jquery etc. The back end dev only needs to know their language, json, and possibly a DB query language (sql?)
6) Most users don't mind. While old phones suffer, most people have modern smartphones and computers, and even angular, arguably the most bloated SPA framework is still only 500kb, which is nothing compared to people streaming gigabytes of twitch and youtube video data every day.
7) The tons and tons of useless javascript and css come from NPM dependencies which people just download to add one thing to their project and think nothing of the size. This is why despite being the biggest framework, Angular projects probably end up growing the least because it already has angular-ways of doing everything you could think of, unlike "smaller" libraries like vue, react, etc. which are small at first but you end up downloading all kinds of dependencies for missing functionality.