I think the “Pensions you don’t contribute to and the amount you get is fixed.” is a bit murky. If you have a pension that probably means you have a lower salary compared to an equivalent non pension job, because part of your labor value goes into funding the pension. But the main thing is 401(k) puts a lot of responsibility on the individual. And as this article points out, if you put a lot put retirement financial planning on the individual, that creates a larger social problem since many people can’t sufficiently do that themselves, even if they are being responsible with what they earn.
But the point is we can’t trust personal responsibility. If a significant volume of the population is basically guaranteed to not invest and save voluntarily for retirement that is always going to be a social problem. Also, there’s the problem of employers voluntarily providing retirement programs. Sure, I think there’s a question of what or how that savings is invested for retirement (pension, 401k, etc), but it seems there needs to be more mandate to require employer’s of a certain size to support retirement plans. And possibly even more mandate to require contributions to retirement plans. The article describes this in Australia: “Australia’s Superannuation Guarantee requires companies to contribute the equivalent of 11 percent of an employee’s monthly pay to an investment account that is controlled by the worker, who can also put in additional money. The “Super,” as it is known, includes full-time and part-time workers and has proved to be enormously successful. With its relatively small population — just 27 million — Australia now has the world’s fourth-highest per capita contributions to a pension system, and almost 80 percent of its work force is covered.”