They did that later, but it is accurate to say that when Mach was first designed, Rick Rashid and others lacked "industry experience". However, they had a lot of practical experience making real systems for academic purposes. The CS departments at U of Rochester and CMU are serious about building stuff.

>was famously blasted by Linus for not having industry experience.

I answered my own question (where to read more about this), and found the relevant information from https://www.oreilly.com/openbook/opensources/book/appa.html

> To put this discussion into perspective, when it occurred in 1992, [...] many companies that are household names today--Netscape, Yahoo, Excite--simply did not exist.

That sure has aged interestingly since 1999.

This is a fantastic read, thanks for linking it. Linus's pragmatic approach really comes to the fore.