Harvard is generally considered to be toward the theoretical end of the computer science spectrum. As part of a recent initiative to bolster their department, they have hired six new professors.
Their three most senior hires (all full professors with named appointments) are from industry. One worked for MIcrosoft in the Boston area and was also an adjunct professor at MIT, another worked for Microsoft in the Boston area, and one worked for Microsoft in Silicon Valley.
Their third most senior hire (an associate professor) is from Microsoft
Of their two most junior hires (both assistant professors) one is from industry (a post doc fellow at Facebook) and one is from academia (post doc at MIT)
In the field of computers there is a very close relationship between the leading edge computer development companies (not IT companies) and academia. People and ideas readily flow back and forth across the boundary with some top people straddling the boundary as adjuncts.
Top departments typically have a mix of “Lecturers” (people who are great at teaching), “Professors of Practice” or “Adjuncts” (who can bridge the gap between theory and “state of the art” practice) as well as Professors doing leading edge research that can translate that research into the classroom.
This gives schools located in a “computer development hub” (such as SIlicon Valley, Boston or Seattle) an advantage because industry research labs can be tapped to teach some leading edge courses.
No one should want to send their kids to a school where the professors research is “decades ahead” of their classroom teaching because by definition their kid will derive no benefit from the research going on in that environment.
Computer Science is not a great example for this thread, because (at least at this moment) it is one of the few areas of academia that is having a hard time finding enough people.