Google is a public company, and I think the average Wall Street investor is even more 'short-term' than VCs. In fact, it should be a surprise that investors are not questioning such spending. What insulates these moonshot projects from investor ire is that as an expense, they are only a very small part of the total revenue of Google.
Page is shielded from such investors by a Board of Directors. Presumably they have a better understanding of Google's long-term vision. It's also worth keeping in mind that Google performs extremely well even viewed from short-term metrics.
