If the enemy is the developer then you've already lost. Its not like cache sharing is how a developer chooses to unmask your anonymity when browsing between sites; they have cookies to do that in much better ways.
> If the enemy is the developer then you've already lost.
It's not that the developer is the enemy.
Pretend I create a website called "Democratic Underground: how to foster democracy under a repressive regime." I'm naive, or I want it to load quickly, or I accidentally include a framework that is either of those two -- some library versions are cached.
Now, the EvilGov includes cache-detection scripting on its "pay your taxes here" webpage. Despite my salutatory goals, shared caching leaks to the government some subset of my readers.
A long time ago PHK wrote some very salient comments about HTTP 2.0 efforts https://varnish-cache.org/docs/trunk/phk/http20.html https://queue.acm.org/detail.cfm?id=2716278 etc. He puts forward the case for a browser-picked client-session-id instead of a server-supplied cookie.