In fact, there are many of them. They are lifetime annuities offered by private insurance companies. You pay into the annuity over the years, the insurance company invests the money for you, and it pays you a lifetime pension when you retire. When you own an annuity, you have a firm contract with an insurance company. When you have an annuity, you don't have to worry that Congress will change the rules.
Many employers already provide pensions for their employees.
If there were no Social Security system, competition for the best employees would inspire a great many more to do the same. Private annuities work. They've existed for hundreds of years. Government doesn't work, although it has existed for thousands of years. Political Social Security is a fraud that can never be fixed.