The idea is not unreasonable, but likely impossible to pass for various reasons. In my opinion, the only way it can happen is for the free market to put pressure on airlines to "need" to size up thweir fleet in order to fill demand at the congested airport. That means, among other things, Congress should not encourage the industry to invest huge money into expensive supersizing schemes for airports that are already overcrowded. Building runways in Bays and adding umpteenth runways against huge environmental opposition is both costly and absurd, especially when other communities are begging to have airlines come and serve, with good local jobs, etc. Has anyone else noticed how bad many airline jobs appear to be getting at these over-sized hubs...?
A good example is SFO. Airlines need to fly heavies into this airport because of it's limitations...and they do. But, efforts to squeeze out smaller aircraft run into heavy resistance. Smaller carriers (and feeders) cry foul and anti-commerce; at the same time, AOPA is very effective at lobbying against limiting civilian access to publicly funded hubs. And efforts to build new runways, well....
The frequency issue is often taken too far. Yes, 6-8 737s/day is better than 2-3 jumbos/day. But, a city-pair like SEA-PDX does not need 40-50 flights/day over fifteen hours, many of them feeders. And it is ironic that many of these half-hourly feeders are routinely cancelled (with passengers pushed to the next flight), just to make needed loads. I wonder how many of these cancellations are reflected in the airline performance reports that weigh so heavily in rising consumer dissatisfaction?
If congestion is a problem we really want to solve, Congress could pass laws that would encourage use of the hundreds of underused (and many unused!) potential US commercial airports. Eliminating the huge advantage the biggest hubs have in raising capital by changing the PFC law would be a great place to start. Perhaps a law that compels airport authorities to demonstrate a workable plan WITHOUT JUST GROWING A BIGGER CONGESTION PROBLEM AIRSIDE AND/OR LANDSIDE before getting approval to instate PFC charges? And, perhaps more FAA money budgeted into airport grants to seed development at the unused airports? These are two examples of laws that would slowly reduce the monopoly effect of the major airlines at our congested, publicly-funded hubs.