People who never worked with some of the bloated sites often forgot third party in the bloating.
Marketing team mandating inclusion of at least one "Tag Manager" (if they are especially bad, there will be multiple).
A "Tag Manager" is a piece of JS that is installed together with an API key in the site... and then it downloads whatever extra JS that was configured for given API key. The actual site developer often has absolutely no control over it (the closest I got once was PoC-of-PoC where we tried to put even inclusion of tag manager behind an actually GDPR-compliant consent screen).
Marketing team gets to add "tags" (read, tracking, chat overlays, subscription naggers, whatever), sometimes with extra rules (that also take time processing!), all without involving the development team behind the site.
Blaming tag managers and marketing departments is quite common and yes while they are problems on some sites many developers overlook the impact of their technology choices e.g. client side rendering, JS based components etc
There's a reason why I speak of "third party", though I guess it might be unclear in english - my bad.
There are three parties involved in the bloating. Management prioritising certain things is one. Developers (including here both programmers and designers and others etc.) not caring enough or otherwise making choices that lead to bloat is second. Marketing team with power to require problematic things added or just going crazy with tag manager is third.
But consider how much of the bloated JS tends to be from external parties, and pretty much everything that isn't CDN-ed frameworks will be stuff either required by marketing, or flat out added through the use of a tag manager.
Marketing team mandating inclusion of at least one "Tag Manager" (if they are especially bad, there will be multiple).
A "Tag Manager" is a piece of JS that is installed together with an API key in the site... and then it downloads whatever extra JS that was configured for given API key. The actual site developer often has absolutely no control over it (the closest I got once was PoC-of-PoC where we tried to put even inclusion of tag manager behind an actually GDPR-compliant consent screen).
Marketing team gets to add "tags" (read, tracking, chat overlays, subscription naggers, whatever), sometimes with extra rules (that also take time processing!), all without involving the development team behind the site.