Would you eliminate Social Security and Medicare?
I think they should be phased out. No new people brought into the system. No new Social Security cards issued. Everyone currently in the system can opt out. You don't get your money back but you get a 15% pay raise immediately. Start cutting benefits to future retirees. Those who have not paid get no benefits. No more SSDI applications.
Same principles apply to Medicare but from what I understand it's in worse shape and even more complicated. They need to reverse the trend and start narrowing the qualifications for benefits. Keep doing that until no one is left.