Reserve a huge share of the blame for the “UX dEsIgNeRs”. Let’s demand to reimplement every single standard widget in a way that has 50% odds of being accessible, has bugs, doesn’t work correctly with autofill most of the time, and adds 600kB of code per widget. Our precious branding requires it.

often we're told to add Google XSS-as-a-serv.. I mean Tag Manager, then the non-tech people in Marketing go ham without a care in the world beyond their metrics. Can't blame them, it's what they're measured on.

Marketing and managers should be restricted as well, because managers set the priorities.

You can still make a site unusable without having it load lots of data. Go to https://bunnings.com.au on a phone and try looking up an item. It's actually faster to walk around the store and find an employee and get them to look it up on an in-store terminal than it is to use their web site to find something. A quick visit to profiles.firefox.com indicates it's probably more memory than CPU, half a gigabyte of memory consumed if I'm interpreting the graphical bling correctly.