There will be a lot of poor suckers. A lot of pension schemes and even social security in the US rely on having younger workers paying into it. It's a huge part of how people do retirement planning.

If your answer is that you are not planning on counting on it for the future then a lot of people will ask why not stop paying into it and keep the money taxed for yourself? It is a significant tax. You CAN actually stop paying into it and then make yourself ineligible for payments out which includes spousal benefits being cancelled. You CAN conscientiously object, it is a provision of the SSA law.

If a lot of young people saw that, they would withdraw from it and put the trust right now into a deficit which would adversely affect the people withdrawing from it right now.

I think there is a non zero probability of this happening regardless for different, uglier political reasons but it doesn't make a lot of sense for people to be forced to pay into something with no promise of ever getting something back.