This is not entirely true, there are many fields in which the T&Cs have significantly degraded over the years.
Well, not to the point that they end up paying to work, but the typical design office engineer's purchasing power was divided by two over 50 years.
That's why I said aviation is not exclusive and that it has happened to other industries. However, engineers have stood their ground, as have doctors, lawyers, and a number of other groups, when the conditions became too poor for them to accept. Not so for pilots.
I totally agree with what you're saying but unless there is a pilot shortage on the horizon and airlines are desperate for pilots it probably won't improve for a while.
So make the pilot shortage a reality by not applying for the jobs. Force the issue.
I know this sounds hard, but I never applied to a company where my pay would be less than I thought the position was worth. Paying for a type rating to get the job lessens the professional status of pilots. It is required training the airline must provide, but so long as a single pilot agrees to pay for the type rating, the airlines will continue to do it. Again, we can't blame the airlines; all they're doing is ensuring the company remains profitable. If a pilot agrees to those terms, well sucks to be them. They're the sucker, not the airline.
If it could be agreed between all pilots that we would never apply to a company where paying for a type rating was required for the job, then you will see the forced pilot shortage and an immediate improvement in WACONS.
It would take about six months to a year for the airline to start feeling the pinch, and maybe another year for them to get the picture that they could not go back to their old ways, but if pilots continue to wait for the looming pilot shortage, then airlines will do whatever it takes to ensure it remains looming.