The airlines don't pay pilots, the passengers do. When the passengers won't or can't pay, we don't get paid.
The aviation industry is far too complex to be controlled by simple supply/demand. There are too many other factors.
Agreed, the industry is very complex and there are many factors at work affecting our current payscales, but I would still argue that it primarily comes down to supply and demand.
Over the past few years, there has been an excess supply of 50 seat regional jet capacity, coupled with decreasing demand in the RJ marketplace. (Ironically, this is due to more pax flying, meaning larger mainline aircraft are taking back flying from RJ's). With no effective scope to protect anyone's flying, the majors have been free to put out for bid almost all the remaining regional flying they want. Regionals with extra RJs are falling all over themselves to underbid each other for the flying, thus managements apply pressure on labor to keep wages low so they can afford the low bids. And up until recently, plenty of pilots (excess supply) have been willing to work at these lower wages.
But now finally, the supply of experienced pilots is starting to dry up. If we ever truly do have a real shortage (we're not quite there yet), and regionals can't cover their current flying with overtime/extensions/etc., then airplanes would be parked and flights would be cancelled. That's when consumer demand would play a role. If every seat on every remaining flight was sold, consumers would eventually be willing to pay a premium not to have to drive. Ticket prices and airline revenues would go up, and airlines would finally raise wages to attract enough pilots to satisfy customer demand.
The only problem is, I don't see the above scenario coming to pass. Either the supply of new pilots will not completely dry up, or if it does, regionals could simply recruit college or even high school grads, and sponsor them through their commercial pilot's license in exchange for a few years of indentured servitude. Factor in the reduced cost of the soon-to-be-new MPL, and problem solved. Too bad ALPA seems to be endorsing the MPL.
As someone else referred to, perhaps the only solution is union coordination that somehow limits the supply of labor through effective scope. Unfortunately, that's easier said than done.