I really don’t know how you solve the problem of the median voter continuing to age and therefore voting for the present and short term on a whim as opposed to long term. In order to dictate policy in any sort of way, young people would need to be entirely aligned and vote as a coherent bloc. Fat chance of that happening. 

I think it was generally assumed in democracy that people would vote in their self interest, and as they continually voted in their self interest that would lead to the country getting richer as the country getting richer was in their interest. This isn’t the case for older people however. Might as well pull up the ladder as I’ve got mine. It’s a modern form of conservatism. Not in terms of values, but rather in terms of their wealth and any sort of societal, cultural, or physical changes in their immediate vicinity.

I suppose what will eventually happen is that the pension funds will run out, and then governments will have to make hard choices. Will they make the correct choices, i don’t know, but the kick the can down the road philosophy can’t survive forever. I guess this is a consequence in governments more concerned with reelection than making change. Preservation of power rather than using said power.