I really wish my experience were that cut and dry. This strategy seems to me to depend super strongly on the quality of the developers/engineers, and their commitment to getting work done (c.f. your examples: Skunk Works, Bell Labs, PARC, etc -- I really wish I worked in such an environment!).
There are people who are good at seeming busy, but who wildly overestimate, take every opportunity to get bogged down on some trivial obstacle, chronically misunderstand objectives/values, can't consistently put three words in a row correctly, and just seem in general to be the weak link; those people need to be managed.