[owl57]

Sure, I didn't mean Linux isn't standing on the (partially the same) shoulders. What I meant is macOS/iOS and Windows teams are unique in shipping general-purpose OSs AND doing so and accreting code and expertise tied to that code since ancient times when "try and paper over the complexities of linux" wasn't an option at all.

[pushpop]

Whether it’s 10 years, 20 years or 30. I don’t think it makes much difference after 10 in terms of the level of relevant expertise you’d expect. Particularly when you factor in staff leaving, getting promoted, etc and new engineers joining. Where Linux differs isn’t it’s age but rather it’s development model being decentralised. FreeBSD might be a more comparable example given the context you’re describing.