Most of these pilots should be smart enough to know they stand a very good chance of prevailing for back pay and damages against these airlines in future and current lawsuits. They should be financially in good enough shape to let that play out.
That may make sense for the more senior pilots. But for those in their first 10 years keep in mind that they had to accumulate 1,000 plus hours of flight time as PIC plus their Commercial ATP rating and Instrument rating. This means either they came from the military or paid on their own.
Pay rates for the first 5-10 years as Flight Engineer or Co Pilot are not enough to become wealthy while working their way up the seniority ladder plus they are likely paying back their civilian training costs.
Doctors and Lawyers get stuck in this early to mid-career situation too. It is harder than one might think to just quit and go into another career that has the potential to cover their debts long term.