Oh boy. The bare necessities of someone is already "additional demand" over that person not being present. Disposable income is a completely irrelevant factor here. In fact, disposable income is the part that doesn't generate the same level of economic demand because it can be saved rather than spent.

And no, it is not easy for investors to outcompete incumbents simply by being more efficient with their employment policies, especially not in a society like Japan. And my point is that employers are not hiring older people even though they could pay them less.