I'm sure 25 years ago people found the idea of buying a home computer (almost) exclusively for gaming completely ludicrous. And still, gaming found a market within the home computer segment.
I know not everybody has tablets, but you guys keep thinking of the wrong kind of games. Many games available for Android tablets nowadays are not very different from games available for the PS Vita or 3DS, which are dedicated gaming devices. The difference is most tablet games are designed for touchscreens, which can be very creative. Some examples of unique and interesting games:
There are also some cool adventure games that play well with touch (Machinarium, Broken Sword, etc...), and all time classics like Metal Slug 3 and Chrono Trigger.
I wouldn't be surprised if we see tablets designed specifically for playing games in the next one or two years. Consider, as well, most modern tablets use multiple wireless communication technologies (NFC, Bluetooth, etc.) and can be paired with gamepads, and can also export their displays. Ideally however, we would have open specification tablets, and not depend on Google or Apple.