for some, 'compiler construction' would count as foundational skill. But realistically nowadays it is a skill that is neither necessary, nor all that helpful in a typical day as SWE. There was a very narrow sliver of time (maybe 95-05) where this was a skill you'd be using outside of your CS class. While I do agree with your basic sentiment of 'CS doesn't teach the same things as 20 years ago', I don't think that's necessarily a bad thing. Those who like to dig to that level will do so on their own (just like not everybody likes to study analytical topology).