clam you clearly haven't read what I wrote, or you'd see that they do grow out of it, my eldest did, and now my youngest is doing. I have two children, nearly three years apart, the eldest sleeps just fine now.
As for the incentive to sleep? Well, we don't greet them with cuddles and games (what kind of idiot would do that?) they are shhh'd and to go back to sleep. However, they are not shut in their room alone, or ignored.
DD1 slept in her own room from 8 months of age (as the "rules" say to. I got sick of getting up to got to her by the time she was 18 months old, so we put her in a normal single bed with a cot rail on it to stop her falling out and that way when she woke in the night she could just come through by her self and get in with us and go back to sleep. DD2 slept in a sidecar cot from birth, and moved into the bottom bunk in DD1's room when she was about 2½ and like her big sister, if she woke in the night she simply came through and got in with us and went back to sleep.
Night waking is normal for babies and small children. We seem to have this idea that they should be sleeping 12 hours without stirring from about 12 weeks of age (or even younger) and it's total nonsense. ALmost everyone wakes slightly in the night every few hours, even most adults. Many people will have a drink in the middle of the night, or a wee, or just look at the clock and register that it's not getting up time yet and go back to sleep. We do this without fully waking up because we are adults and we generally know where we are and just settle back off to sleep again.
Babies and small children don't have this rational ability to think "it's ok, mummy is next door" or what ever, so when they wake, they wake. If you read research about this you'll see that theres nothing odd or strange about children waking in the night and not wanting to be alone (you sleep with your DH/P, why should they not be allowed company?), what is odd is the way it's treated in this country/society.
Oh, and I'm not saying that I like the broken sleep I've had over the last 6 years, or that it's good, but, I accept it as normal, and that caring for my children is the responsibility I took on when I decided to have them, and that responsibility doesn't go away just because it's before 7am.