This strategy would quickly lose its merit outside of Harvard. Failing to gain tenure at Harvard is the expected outcome, so a) the sense of rejection is less, and b) your remaining job prospects are good because this is generally recognized (and it's Harvard). Asking somebody at a high-tenure-rate, second-tier school to treat their tenure track position as an extended post-doc is essentially asking them to have a fa…
It would seem like anyone worth their salt in computer science could get a corporate job after 7 years at any school, especially Harvard. It seems like the concept of having a failed career is much less than if the Phd was in Philosophy.
That's sweeping, overstated, and unfair of me, but the job skills are quite different. Applied, directed research aimed at producing tangible and sell-able results is very hard, and by-and-large not what they do, at least based on who applies and interviews (which is of course a terribly biased and perhaps non-representative selection).