And you need to trust the compiler.
Unless you build from the transistors up you have incoherent security theater.
https://news.ycombinator.com/item?id=33899478
If you want to be 'really' secure, you can trust noone. No silicon, no software, no compilers, no certificates, no power grids, no networks, no friends, no coworkers, no nothing.
But that is no life I'd want to live. So I pick my battles and make sure my SecOps is better than 99.9% of the people out there. For me that suffices. YMMV.
That's the job of traditional Linux distros.
> or sandbox it sufficiently
That does nothing when it comes to E2EE.
I share this view, but I also think it's very difficult to verify such validation is happening. I don't think most end users would want a distro stable enough to meet a high review bar.
> That does nothing when it comes to E2EE
Not all components need access to the keys or user data. Reducing attack surface reduces the amount that needs to be validated.
So update decisions could have a calculus like, "it's already working; I don't need any feature updates; I'll stick with the stable version" and then attempting to evaluate each CVE on its merits vs. the mitigations offered in each update. (Of course, the way developers like KeePassXC are fighting with the NVD shows that CVE descriptions can't even be trusted these days.)
I foolishly disabled automatic updates for my consumer-grade WiFi router, and I didn't have a plan for manual updates, so it got pwned. I read a few CVEs and I'm fairly sure I know how it was pwned remotely. Thankfully it didn't seem to be making lateral moves into my computing devices, or acting against me personally, and I was able to disinfect the router and put it back into service. The vulnerabilities that enabled the pwnage were fixed by an update which was released about a month before the pwnage, so if I'd been on automatic updates, I probably would've been safe. And that's what the hackers count on.
I would take an unaudited patched-for-known-cves over just not updating any day.
The lack of a distribution trust model for the web has long bummed me out, but even snake oil E2EE is a good thing because it makes an active (and potentially detectable) intervention necessary to exploit a client.
Supply chain attacks remain a huge mess. Unless you can validate the worthiness and authenticity of an update, or sandbox it sufficiently, most software can become a threat.
A more manual, opt-in update process for web apps (via service workers) would be a nice innovation, but I doubt it would provide much more safety to non technical end users, since the harder question is whether a particular update is harmful. Solving that verification problem is the crux of the issue regardless of how rapidly software updates.