This is the essence of the problem with Android tablets, developers are not taking them seriously which is a shame because the hardware in some cases is top notch but much of the software is currently pretty crappy.
Its hard to optimize for a wide variety of sizes. If some tablet were successful enough, developers would target it. Thats why Google is doing the Nexus 10. Trying to make it the standard that developers write to.
The other problem is that by selling the absolute cheapest devices that can be made, Google is targeting the consumer who doesn't want to spend any money. That is not a good starting point to try and convince a developer to spend thousands or tens of thousands of dollars trying to develop an app. Large companies who need a presence on Android can afford it to have coverage. But as a money making venture for a smaller developer, iOS is a much better bet. At least for now.
I wonder if Windows 8 will get any traction. I'm not sure all the licensing and distribution options and restrictions. But if its possible to write an app that works on a Windows 8 PC, Windows 8 tablet, Windows 8 phone, with a similar code base, that might be an interesting target because of the shear size of the Windows PC platform and its potential for growth.