But Sony isn't doing that. You need to voluntarily install the update. Furthermore, a non-updated console is still perfectly functional. It can still play games. Now if future games don't work with it, well there was no guarantee ever made by Sony that it would work with future games or services.
I have to disagree.
If I bought my PS3 to play games, then it should play all current and future games without having to update its FW. The guarantee is the PS3 logo on the game box.
If I decide to play it online, then I all bets are off as the service (PSN) isn't something that was purchased.