Who do you think would be directly involved in enforcing RC flying if the AMA couldn't handle the job?
Uh, the folks that are actually enforcing it now? The public freq Dont Interfere rules, why would that change if the AMA went poof.
The AMA restrictions on it's club members dont mean squat to non members flying around... but the FAA & FCC regs hold the AMA by the brassones. AMA does not 'handle the job' now, it hanldes it for its members only.