Currently, potential political candidates with newer and fresher ideas face barriers that are almost insurmountable.

They can’t get on the ballot if nobody has ever heard of them. But in order to be heard from, they have to either raise large sums of advertising money (typically from entities with vested interests in proclaiming the marketplace to be perfect), or go far enough to the left to mobilize the die-hards on that side (usually too far to be practical or acceptable to the mainstream).  

More centrist yet innovative approaches—although precisely what most voters seem to want—rarely generate the kind of enthusiastic early support that’s needed to get a name on a ballot.