BreakfastMan said:
Actually, that Steam one is highly unlikely. Steam has an offline mode that generally allows you to play you Stream games just fine.
What if an update bricks Steam?
Or Valve goes bust?
Or their publishing deals expire or go south (like say... Crysis 2)?
Or your Key corrupts and bricks the game (Like Company of Heroes)?
There are a whole bunch of scenarios where you lose access to a game(s) on Steam, or keep access, provided you never, ever need to repair or validate the install ever again, some of which have already happened, not all of which were fixed (thanks EA and Ubisoft!).
But people get complacent because Valve are generally better behaved than Ubisoft or EA are, that doesn't mean their system is perfect or that they'll maintain their standards forever.