I was reading the How to Buy Into Android at the Worst Possible Time [HUMOR] on http://phandroid.com and it made me think about this topic now the above link wasn't meant as a rant or flame war but rather to highlight the issue that when you develop the OS and the hardware you are sort of responsible for backwards compatibility.
Take Apple for example they dropped support for the first generation of the iPhone's lately and i heard that the iPhone 3G wont be getting update iOS4.3 as a consumer I'm happy for this because I got updates for a while on my device. I don't know if the above is generally true for every android device, but it highlights that device manufactures are going well its not financially viable for us to upgrade existing devices as that will break a sales channel "We want people to upgrade their hardware" as that makes us money. So why should they push through an OS upgrade. What needs to happen is that people get the option to upgrade with backups taken before and the ability to restore to previous OS if the upgrade doesn't work. The update should also be flagged by your manufacture as tested with your device if they have tested it and it works so people can either. Choose to wait for the manufacture to tell them its OK to install or follow a blogger/website that tests the device with the latest version and lets you know its working before you download and run it on your machine.
I'm not writing this as a I'm an Apple fan boy we win sort of thing, but rather I'm a consumer this is how it should work.
Traditionally with a PC you get a OS and you can upgrade OK normally you have to buy a new OS (Mac & Win) with tablets you lose this capability you will have to either hack you tablet of choice or hope your manufacturer pushes an OS update out.