I can imagine that Facebook and Google liked the way Angular and React allowed for more advanced tracking. But it seems like you're giving too much weight to that as a primary cause.

From my memory of working through this time, it was driven more by UX designers wanting to have ever more "AJAXy" interfaces. I did a lot of freelancing for design agencies 2006 - 2016, and they all wanted these "reactive" interfaces, but building these with jQuery or vanilla JS was a nightmare. So frameworks like JavaScript MVC, Backbone.js, SproutCore, Ember.js were all popping up offering better ways of achieving it. React, Vue and Angular all evolved out of that ecosystem.

That’s a good and logical story, but it doesn’t match the reality in my experience.

Companies use SPA frameworks for the same reason they use native apps, to make a “richer”, more responsive, more full-featured UI.

Analytics is typically done in a separate layer by a separate team, usually via Google Tag Manager. There might be a GA plugin for your UI framework, but it can work equally well with plain HTML. GA does use a bunch of client-side JS, yes, but it’s not really a framework you use on the client side, it’s just a switch you flip to turn on the data hose.

In my experience, trying to add analytics cleanly to clientside UI code is a complete pain. Trying to keep the analytics schema in sync as the UI evolves is really hard, and UI developers generally find analytics work tedious and/or objectionable and hate doing it.

Google Tag Manager is the big story in adtech, and I think it comes from and inhabits a completely different world from Angular, React etc.

You can do all that with vanilla html. Cursor tracking, scroll tracking. With HTMLX it makes it trivial.

React isnt a SPA framework. It’s a component framework. It has no router or even state management. ExtJs is an Mvc framework in JavaScript and can be used to create a full spa app without additional libraries. It also came out in 2007. There is also ember that also predates react and is another mvc framework by the people who did rails.

This is not correct. SPAs and web components were pioneered by Google with the introduction of Angular. Later, Vue was invented by a previous Google employee who had worked on Angular. Finally, Facebook came up with React (it's a "reaction" to Angular) because they could not be seen using a Google product.

If anything, SPAs make metrics harder because they hide the real behavior of the page in local JS/TS code and don't surface as much or any information in the URL. Also, fewer server interactions means fewer opportunities to capture user behavior or affect it at the server level.