Like, with the US privatized medical system and its parasitical medical insurance system, we can see how medical costs are higher and overall health outcomes lower than in countries with single-payer/national health care.

And if I happen to choose a health insurer which decides my cancer treatment is inappropriate, I'm either bankrupt or dead.

Yes, I'm still dependent on healthcare, but one is better aligned to my health.

Similarly, the personal pension system requires staff and/or custom software to handle customer relations, and the individual funds have marketing budget to convince people to join. This disappears with a nationalized system where it can all be part of the same social security system, and benefit from the economy of scale.

Furthermore, companies justify all sorts of unethical practices because they point to all the (abstract) pensioners who will lose their retirement, which relies on those pensioners not being able to say 'no, don't do it in my name.'

While something like the Government Pension Fund of Norway can select funds and influence the corporate governance in a way which is aligned with national goals.

Yes, there are all sort of ethical funds I could invest in. The paradox of choice and my complete lack of expertise means I must hire that expertise, like when I got advice when I set up my account.

Furthermore, if I happen to select green energy stocks, but they go down the toilet after the invention of Mr. Fusion, I'm currently screwed. While a public pension has the mandate of supporting everyone.

Yes, I'm still dependent on stock investemtns, but one is better aligned to my retirement.

Lastly, the government can raise money from taxes. The government can pay for more nurses and doctors, and training hospitals. The government can pay for high-quality retirement housing. The government can do a lot of things that a private pension plan cannot do.