They do that, this is what their various Labs and subsidiaries and internal accelerators are there for. The issue is that people figure out it's associated with Google and then expect it to be maintained as such.
I do wonder how people figured out that Google was associated with Google+, Google Inbox, Google Reader, Google Talk, Google Video, Google Wave, ...
(I'm just kidding; I don't actually hold a grudge against Google for terminating projects. Although I do miss Inbox. And it does looks like Google Labs was killed too?)
That's fair enough, I suppose, though I think those are also primarily where the "Google kills everything" reputation comes from - not the Labs products.
