Well, one might notice "everybody" has to be a rhetoric exaggeration, since there's absolutely no way even remotely close to "everybody" would have any codebase

Well, one might notice "everybody" has to be a rhetoric exaggeration, since there's absolutely no way even remotely close to "everybody" would have any codebase at all whatsoever, not to talk about 20 year old legacy. Right? Second, I was responding to a comment talking about "existing, critical, real time applications". Of which a huge number of cases do have existing, very old legacy codebases. Third, I fail to see what you tried to bring to the conversation. If your only problem was with my rhetoric, see above.