Google hasn't been terribly successful in tablets so far, and that is because of more than one reason. They were caught completely off-guard by the iPad, even though they shouldn't have been. After all, there were others starting to talk about capacitive touchscreen tablets years before the iPad appeared, and there were even rumors about Apple working on a tablet at least a year before it finally appeared.
And yet it still took Google a full year after the iPad's release to come out with Honeycomb, their first tablet-optimized OS, that wasn't even ready, and it was obvious from day one. Also, to this day Google is still not pushing developers to write tablet applications. Yes, there are not a whole lot of Android tablets out there, but at least sales are picking up, and if were really aggressive with this, they could get a lot more developers to make tablet applications, which are sorely lacking from the Android tablets.
Larry Page believes that things will go a lot better in the Android tablet market once there are more low-cost tablets out there, and it seems to me there are really hinting at their own Nexus tablet. But something people missed from his speech at the earnings report, was that he believes tablets are just part of the equation, and they want Android to be an entire ecosystem of all sorts of devices, that are all around you:
"I think people are going to get a lot more devices. We see kind of a convergence between all the services on those devices. Right now, I feel like each device you have is kind of a hassle to deal with. You're thinking about each individual device. I think that's not really right.
I think you're going to have a pretty unified experience and a great experience, from user point of view, and you won't have to manage all these devices. So I think you want to think about all these screens around you, working seamlessly and working well for you, and I think obviously tablets are important. We have Google TV. Big screens are important. Computers are important. Phones are important. All those devices are important, and I expect that they'll work well together."
In that case the tablets are just a component, while smartphones, TV's, laptops, smartwatches, Google glasses and other types of devices with Android that perhaps don't exist right now are all the other components of this ecosystem. Still, so far Google hasn't proved that it can be successful in another market besides smartphones, so even if they believe that Android can be destined for more than one type of device, they need to win these markets one by one, not by going into these markets with a weak effort, and ending up being a minor player at best.