Re: The purpose of Steam machines is to attract console players @ Valeyard
And thats the thing with the Steambox. There will not be a problem with backwards compatability. The games you buy today, will still play on your Steambox (upgraded or not) in 10 years. There's no need for you to pull an old machine out of the closet, in order to play your old games.
You also wont need to buy a whole new machine when the latest games come out. No more throwing away a perfectly good device, just because the console maker wants to sell you a new piece of equipment.
It's true you will probably have to upgrade parts of your steambox over time as games progress (just like on a PC), but adding some memory, and more hard drive space is a doddle in a PC. Additionally, the pace of PC upgrading to meet high spec games has slowed down massively since the 90's. My laptop is 4 years old, and I still havent seen a PC of software I cant run on it. The fact is that (provided I dont drop and break the thing), I expect my laptop to last me another 5-6 years and still run pretty much everything being released. A Steambox should have the same effect which is why they are being looked at so eagerly by many people...