The way I see it, people don't spend $150,000 on education and training for an $18,000/year job. They spend $150,000 on education and training in the hopes and potential that they will one day be that SWA, UPS, FedEx, etc. captain, making close to $200,000/year.
Other than first year FO pay at a regional, salaries are not that bad. I think there is a reason that first year regional FO pay is so low. It is the same reason first year FO and captain pay at UPS is only $27/hr. The second to third year FOs at the regionals, that I know, are making on average, about $40,000/year. Some more, and some less, depending on the airline. I know one guy who made $50,000 his second year. Those salaries, except for the first year FO, is about what one would expect to make starting in other careers as well. The exception being those becoming doctors, lawyers, and other career fields that require a special degree. Those salaries are certainly livable for someone who is young, single and new to the industry.
Captain pay at a regional is certainly livable. I know a couple of five to six year captains at the regional, and they make between $70-$80,000/year. In other career fields, salaries tend to top off at around the ~$80,000/year range, and some not even that high. Plenty of people also own homes, have nice cars, and are raising families on the above salaries, and less. I think this is why some people decide to spend their career with a regional. They are making a good salary, holding a line, know what days they will have off, and have a good QOL. They don't want to give that all away to start at the bottom again, even if it is with the majors, even if it means a pay raise.
No I am not sticking up for pilot pay. Here is why I mentioned all of the above. I don't think the $150,000 is for the first year regional FO pay. I think it is for the potential later on. This is why I think if you start slashing major pay, you will, in the long run, begin to see pilot applicants taper off. I agree there will still be those willing to fill the classes and fly for free. But, even they will eventually realize they have to eat, and it is not worth it. You will then see a tapering off of those willing to fly for free. More, and more people will become content with entering another career field, and simply buying their own airplane to fly for fun on the weekends. When this happens, the airlines will find themselves with a true pilot shortage.