The entire system or just parts of it? Remember that Social Security isn't just about retiement, it also includes disability for those unable to work. The retirement fund is the part we see so often in the news as being on the brink of failure. I would argue that anyone with at least 20 years to retirement should plan on not having SS benefits available. Build your own retirement and then if SS is available, it'll make a nice bonus. Only a young fool would depend on it being there. Take an active role.
Eliminating the disability aspect is unthinkable. In some form it must exist to help those who are unable to support themselves. Imagine going blind suddenly. Think of the time and efort it would take to be able to work again. Social Security disability helps fill that void. For the mentally ill, who have a difficult time maintaining a job, it can be the lifeline to keep them from the streets. So, if SS were eliminated, these services would have to be picked up elsewhere, either federally or at the state level.