I bought a new 32gig 3GS 12 months ago (a month before the iP4 was announced) and I don't expect iOS5 to come to the 3GS. From the horror stories my friends tell of their 3G's going to the dogs with iOS4, Apple would be stupid to pull the same stunt on the 3GS.
Hell, the iPhone 4 is one year old technology at this point.
Wow! A reasonable person.
I get so annoyed with people bitching that Apple are evil for not supporting two year old phones cause some one might have bought it more recently (This annoys me cause in most cases it is from some one who has the phone not supported but has had it a while and isn't one of the ones affected but realizes it doesn't look as reasonable to whine that they phone they've had for 2 years isn't going to get support).
1. The phone is still two year old technology even if you bought it now.
2. Most people who bought it this recently don't really care, a smartphone isn't their biggest priority. The only person I know who bought a 3GS recently was dragged into getting a smartphone and figured for 50 dollars it was worth it. He doesn't really need or want much out of his phone honestly. Anything it does extra over his old dumbphone is gravy.
3. Most people who care will realize it is an old phone when they buy it and either decide that for their budget they can deal with older technology (and can understand it won't stay relevant for long) or they buy the newer one or even wait for the newest one to come out.
4. And the rare few who did buy one not realizing it was old and likely not to be supported for as long... do your research before buying first if how long an item is supported is that important to you that this would upset you. It wouldn't be hard to learn that it's an old phone. I'm sure the apple salesman will easily tell you that and tell you why maybe a 4 is worth that extra money!
And as for some one who had the phone since it was new... they supported it for 2 years with the new OS updates. Longer than most phones (my previous phones never got updates to the OS.... though to be fair they were all dumbphones, but they were still running some sort of customized OS). It still can do what you like it for.... if you want the newer features, you can get a newer phone with renewing your contract and you won't pay that much for it.
I certainly didn't gripe when they barely supported the 3G last year (and fully expected by this year it wouldn't be supported period. Sure, Apple was quicker than what I expected but judging from complaints on how badly the 3G ran iOS 4.0, it was not surprising at all they just gave up supporting it period before iOS 5.0).
I certainly expect the 4 will be barely if at all supported next year. Actually, I think I'm going to wait on 5 to see how fast it runs on the 4 (I know that iOS 3.0 did make my 3G noticeably slower, not intolerably slow but I did notice that it took longer to load apps and lagged a lot more).