I think the 2 biggest contributions many big corporations bring are that they do participate in maintaining the software (some at least) and that they use it. I

I think the 2 biggest contributions many big corporations bring are that they do participate in maintaining the software (some at least) and that they use it. Imagine where would Linux and a lot of FOSS would be if those companies weren't pushing it around to users, making it ubiquitous. I know it's a cynical view but it's exactly the principle of an app store: 1) one company puts in all the effort to develop a great product that would otherwise go nowhere unless 2) another company gives it the necessary reach without otherwise contributing too much.