It's not that far from the truth, in that much of high-performance chip design knowledge is acquired through on-the-job training / working with more experienced

It's not that far from the truth, in that much of high-performance chip design knowledge is acquired through on-the-job training / working with more experienced people. Learning computer architecture in school just teaches the basics about how digital logic and CPUs work (frequently with 1980s designs), not how to actually build a screaming fast 4 GHz chip that you can tape out and get high production yield on. So Intel, Nvidia, etc. train lots of engineers that go on to start other companies (or move between companies).