I think a 401K or a Defined Contribution plan is the right way for pension systems.

I believe the right approach is to help people build assets while they are of working age for retirement,
allowing them to use what they have personally accumulated.
The argument that we can simply collect taxes later and use a pay-as-you-go system
seems to fail to overcome the reality that it eventually succumbs to moral hazard and turns into a Ponzi scheme.