> A browser is too complex but an OS and SSH aren't? Yes, most certainly. A browser is running adversarial third party code all the time as a matter of course

> A browser is too complex but an OS and SSH aren't? Yes, most certainly. A browser is running adversarial third party code all the time as a matter of course. While browsers do a good job at isolating, expecting this to be perfect is way too fragile for a security critical requirement like putting all passwords in one basket. An isolated and minimized OS install, much easier to harden. Never runs any code you don't know about.