The whole notion that everyone is responsible for product is pretty mainstream at this point, increasingly so since the whole "lean startup" concept gained traction.
20% time is not nearly the same thing as "we hire you, you figure out a team to go work on, leave those teams at any reasonable point, and feel free to start an entirely new full-time project as long as you can get buy-in for it, for there are no managers or bosses to tell you what to do".
20% time policies are another variation.
The whole notion that everyone is responsible for product is pretty mainstream at this point, increasingly so since the whole "lean startup" concept gained traction.