Just in the WAS-RDU market, the fares have returned to approximately what they were pre FlyI. I think the walkups are too high, but apparently someone is buying them or they'd be lower. I just bought a ticket from DCA to RDU, and paid 218 for it. It's obviously higher than during the FlyI era.... but I was paying anywhere from 175 to 200ish pre FlyI for the advance purchase fare.
In 1984...I paid 188 to fly my 14 year old self from RDU to DCA to see my aunt for the summer. Yes, I'm a big enough nerd that I remember the fare....because I'd earned it all cutting grass. I was an FT'er in the making even then. That was higher than some of the other fares that had been paid for the same summer trip around the same time...but...still, I think is indicative of something.... with the exception of the occasional flirtation with the 29 dollar trash fares by various airline entities, discount fares haven't risen all that much over the last 20 years....at least in that one market.
As a previous poster had said, the shareholders of FlyI have subsidized the travel habits of folks (myself included) to the tune of several hundred million dollars. It had to end sometime, but I sure did enjoy it while it lasted. Are fares too high now? While some of the walkups are a little stratospheric, I don't really think fares are too high overall. If they are, they will surely come down. I know I have a price-point for that WAS-RDU example that I will not pay. We're not there yet.... but we are getting closer.