Not everything is about privacy, and arguably privacy advocates have done a lot to harm our ability to have a trusted internet by conflating verification, encryption and anonymity.
The most annoying thing about HTTPS everywhere is that it ruins cacheability. This is a problem the distros solved ages ago by signing their content but acknowledging it's mostly pointless hiding it in transit.
But its absurd that in HTTP2 we have out of the box encryption, but we don't have a mechanism for doing authenticated caching.
> arguably privacy advocates have done a lot to harm our ability to have a trusted internet
We don't have a trusted internet. Not when a country on the other side of the world can mis-configure BGP and re-route all traffic through them. Not when our ISPs intercept and modify our traffic. Not when there are nearly 10x as many "trusted" root certificates as there are nations in our world.
The internet is the wild west, and we need to protect our computers from it. Currently, encryption is our best bet for doing that. If edge caching is a casualty, then so be it.
If someone can come up with a method for protecting content from end-to-end while keeping it secure against tampering and eavesdropping (because this too matters, both to us in the first world and the majority of others who are not), then let's start getting it put in place.
Agreed that unencrypted signed static assets provide a vehicle for activity monitoring.
Your statement can be misinterpreted to imply that merely by encrypting all traffic, such analysis can be prevented. There's plenty of metadata in a typical encrypted page load that can be used to do so.
For example, the view-discussion page might download three static assets, a js file, and two CSS files, one small and one large, whereas the post-comment page might load zero assets and js files, and one small CSS file.
Point being, making a privacy-protecting website takes careful planning even when fully encrypted. As such, it'd be great to have tools (such as signed content) available for performance optimization. Sure, naive usage might lead to attack vectors, but naive usage of HTTPS already leafs to many such attack vectors anyways.