Sure, but he decides how to allocate resources, make acquisitions, etc. across over 100k employees. If he decided to pull another Google+ he could easily destroy many tens of thousands of engineers’ worth of labor. And it’d only take him a few hundred hours to make that decision, set up the org to lead the project and delegate the execution to them. Putting those engineers on something that actually makes money and is a viable business like Cloud could do the opposite.
It’s not about the time it takes him to make these decisions so much as the quality of his decisions having potentially massive $ impacts on the company’s performance.