I guess one way they could have done it is to spin out companies with enough money for 3 years of runway (with non-obscene compensation packages) for a minority

I guess one way they could have done it is to spin out companies with enough money for 3 years of runway (with non-obscene compensation packages) for a minority stake in the company and a 2 year option to buy a majority stake for N times the valuation at the time of spin-out. That way they can give the product a chance, motivate the people who jump aboard and have the option to buy back the company within a reasonable time frame if it proves to be a success. It would also give Google an incentive to promote the company to some degree and perhaps channel business opportunities their way. (Or some variation of the above). Back when I left Google I would have been happy to take a deal along those lines.