[chc4]

Chrome has the most vulnerabilities because it's the largest browser by market share by a mile, and so has the greatest number of eyes on it. You also can't extrapolate "it was never really secure" from that: practically all software has bugs, especially multi-million line codebases like Chrome. Relative to the average C++ program Chrome is exceedingly secure, and likewise Chrome has been constantly on the cutting edge of introducing new security mitigations. "Is it secure" is not a binary property.

[irundebian]

It can be a binary property if you define security as a proof of absence of runtime errors which is possible to achieve today.

[saagarjha]

This isn’t really possible to achieve.

[irundebian]

It's possible. You can prove absence of runtime errors with Ada/SPARK (which is using theorem provers).