2) Lots of young adults are going to chase the best opportunities in their fields, which are not accessible from the towns they grow up in.
3) Even only children don't get to inherit the house until parents die or move to a retirement facility. This is moving later and later into middle age, well after the "I want a house and marriage and kids" stage.
I don't think inheriting housing is a solution.
If houses could easily last 100-200 years without structural alteration being necessary then some generations would never pay for housing, just as we don't really pay for the capital cost of building most roads but the continued upkeep of them.
[1] http://freakonomics.com/podcast/why-are-japanese-homes-dispo...
Except inheritance comes when you need it least: late middle age, when the house is already paid off or close and there's little time for savings to compound before retirement.
Paying for (most of) your children's education is a much more effective form of inter-generational value transfer: it comes at the time young adults face the greatest expenses relative to their earning power, and lets them reap the benefits of a high-end career without excessive debt (so they can actually build wealth).
But if housing is treated as a more disposable asset (which is presumably less efficient in many cases than updating and remodeling) the cost of that decreased efficiency comes from somewhere. Perhaps from a grandchild's college fund.