Big companies are more likely to give back to non gpl code in my experience. The gpl scares them enough that when they use it they isolate it carefully so they don't have to make changes. Non gpl code (depending on license terms of course) get embedded where it is easier to need changes and then a desire to keep up with some other feature means they contribute back.

Of course either way they are a business and will be careful. Their core business will not be contributed.