I think blaming America's problems on gerontocracy is correlation-causation confusion. The reason we have a gerontocracy is that ordinary rank-and-file voters are too cynical and individualistic to participate in politics.
Nations haven't tried to implement mass immigration because they are woke- it's a last desperate gamble.
The power balance of local politics and national politics also got changed with TV and the internet, things which would've happened regardless of how good a 'generation' is.