If you've made enough money during your working life to invest in a portfolio that will now support you in comfortable leisure in retirement, congratulations.
You don't need to be a major plutocrat to enjoy the advantages of the system that they have designed. Investment for profit is open to anyone who wants to buy in with whatever spare money they have lying around.
Many employers offer pension plans. At higher income levels, the pension can be a considerable inducement to take a job and do your best to hold onto it. Keep your eyes on the pot of gold waiting in the luminous fog of the future.
If your employer doesn't offer a plan, you can still shop around for a mutual fund, or piece together your own collection. Some people are good at this, or lucky. The more money you have, the more luck seems to find you. It isn't insider trading if it just comes up in social conversation, right?
However you collect your pile, remember that you are being supported by the labor of others. The higher your income during your career, the more you were paid with money that was denied to others. The income on your investments is almost entirely money that is denied to others still working. This does include the CEOs and other top management at profitable corporations, who have to sacrifice some of the profits to pay investors. It's all part of the game. They're well compensated enough for it to be a game for them.
Critics of Social Security complain, among other things, that retirees now are getting money put into the system by workers who have not yet retired. The active workers are subsidizing the retirees. But that's exactly how an investment-based retirement plan works as well. The money that private industry generates to pay a return on investment is made using their active labor force, or otherwise stressing the active labor force by laying a bunch of them off and buying back stock with the money saved on payroll.
The only way to save for retirement without relying on younger people to pay your way is to hoard gold, and hope that it still has value by the time you try to trade your nuggets and ingots for the real necessities.