If you say, “We should have invested more,” I point you to the 40% of current retirees that were not in a position to invest because their jobs didn't pay them enough above the cost of existing. And then there are any number of events, such as age discrimination, common medical issues, divorce, and bankruptcy, that destroy retirement plans.
From what I can tell, it's not possible for the vast majority of the population to be able to save for a 20 plus year retirement.
One of the things that keep people from saving are the activities driven by their investing in the stock market. To increase returns, "Activist investors" and private equity drive companies to shed jobs. You shed a job, you destroy a person's ability to save for retirement, which makes them more dependent on the social contract of Social Security and Medicare.
Cutting benefits will only cause suffering. The cost will fall on society in other ways in terms of elderly homeless people filling the ERs, begging in the streets, or committing suicide. Is it time for a "Modest Proposal II"?
For example in the year 2000, people aged over 65 were 12.4% of the U.S. population. Today, that demographic has grown dramatically to 19% of the population. That's fewer people working and paying taxes while also simultaneously drawing more from medicare and social security.
This doesn't mean it's "impossible". But to balance the budget today without major spending cuts would require raising taxes 39%. It's just so different than it was then to make the math work out.
That gives a lot more time to phase in any longer term changes to those programs.
Taxes will go up, voluntarily or involuntarily. If we didn’t want to get here, well, should’ve never spent so frivolously on tax cuts for the wealthy and a bloated military that is unable to pass an audit. But we did, and that debt is going to have to be paid back, with interest. It’s impossible to grow out of this debt, and there are more workers than very wealthy people and their politicians.