You make a good point that software not written in C++ might need less security hardening elsewhere.
But sadly, the reality is that Firefox, Chrome, Safari and Edge are all massive C++ codebases, with lots of security problems. Until we fix that, browsers will need to protect their users as best they can, and that means removing dangers like unsigned addons, overly-flexible addon APIs, and so forth.
Perhaps some users would be ok with a browser with less security and more flexibility. But by default, browsers should be safe, since 99% of users don't understand software and much less software security.
But sadly, the reality is that Firefox, Chrome, Safari and Edge are all massive C++ codebases, with lots of security problems. Until we fix that, browsers will need to protect their users as best they can, and that means removing dangers like unsigned addons, overly-flexible addon APIs, and so forth.
Perhaps some users would be ok with a browser with less security and more flexibility. But by default, browsers should be safe, since 99% of users don't understand software and much less software security.