They have since 1984. It's a common misconception even to this day that they don't pay into the system.
Some do and some don't. The idea was that they were already paying into a pension plan that is likely to be more generous than SS anyway. Plus if we force this, as long as there are public pensions out there we need to deal with the WEP and the GPO as a matter of basic fairness.
I like the idea of continuing to increase the retirement age as life expectancy increases, but I think it should probably be done infrequently -- say every 5-10 years -- to avoid chaos and constantly moving the goalposts on retirement planning. At some point it's good for people to have some certainty. Perhaps I'd say that once someone reaches the age of 50 or so, they shouldn't have their retirement age adjusted again (as you get close to retirement age you need more certainty for planning), but below 50 it could be adjusted every 5-10 years.
I suspect lowering the payroll tax rate is DOA.
How is this revenue-neutral? Both raising the benefit amount and lowering the payroll tax put even more pressure on solvency. Or did you mean *lower* the benefit?
I'm not against a long-term switch to a system whereby people "own" a portion of their contributions instead of just relying on future generations and their ability/willingness to keep the deal, but I doubt that SS will ever completely be eliminated.
My biggest concern with raising the retirement age is that there is already rampant age discrimination and not many want to hire the older folks any more. Increasing the age at which they can collect will mean more older people in the job applicant pool when those already there have enough trouble finding work already.