If any company would create cryptocurrency it would be the same as paypal. I see no point in this. The phenomena of bitcoin is its open source and no government or other control.
and google understands the concept of open source.
They can simply decide to start recognizing/supporting a currency and that would be about the same as them starting their own, except that it would already come with a userbase.
That would likely have the highest chance for success? Rather than starting from scratch like the alts; although, I think they would have success that way, too.
Just not sure if that would be a logical addition to their business model, but I'm sure they have someone analyzing it.