People (us, me) and organisations supported and encouraged the use of a huge codebase in an unsafe language, wanting speed and features over security and test coverage
We were all drunk and manic frankly
Were? I haven't seen any serious move towards SeL4 and userspace written in a memory safe language..
The only serious move is kernels adoption of Rust, but for example in Linux this is restricted to 'non core' components.
And while Rust is obviously safer than C, it isn't really 'security focused' for example it still have supply chain attacks, which would be 'impossible' if it used capabilities..