This is interesting as it seems to vary a lot. We rent our home, and have always rented since we had our son (11 in August). I got pregnant ill advisedly (in terms of life planning, not in terms of having our much loved son!) when I was in my final year at university and my partner was in his first year. Council flat for three years (I worked full time, but rent was VERY low - £235 a month!!!!), and since we both did PGCE it's been private rentals.
My parents have a 4 bed detached house in a very desirable area, mortgage free, but are now both recently retired and have no cash spare, unless they downsized, which they COULD (no kids at home now) but why SHOULD they?
I actually don't care at all that I don't own my home. If we bought it, and it is falling apart a bit and has in the last year needed new floor throughout (wood worm), a new boiler and a new cooker, we would have been absolutely screwed as living to pretty tight budget - all these very expensive jobs were landlords' responsibility.
If my son needs an inheritance - well - not to sound callous, but my very wealthy grandparents and parents will presumably not live forever, although I hope they last a good long time, so he can have that!