But eg the 3GS was only sold in the states NOT eg Europe (it hasnt been sold for about one year now). So Apple doesnt sell low-end model at all in the rest of the world.
There is a difference between what Samsung and Google did.
Even if Apple owned all touchscreen patents (which it does not), it would be unrealistic to expect no one else on earth can ever make all-touchscreen smartphones. No more that it could have prevented GUI and windows to be adopted by non-Apple computers.
But it would be reasonable to expect touchscreen phones could be designed to be distinct from iPhones. This is where Samsung seriously over-stepped.
Off-topic of course, that's not true at all. India immediately comes to mind as an ongoing market for Apple's 3GS. Further, Apple themselves have reportedly decided to position the 3GS for the "bargain-shopper" pre-paid market.