I'm in the same position. I'm lucky to have a flight instructor job, and it keeps me current, but I get like 150 hours a year and it will take me 8 years to hit the current required experience of the airlines (not the money requirement, luckily some still require experience). I have a job outside aviation, and I am happy with that.
I consider paying for a TR with no contract signed for an airline just as "pay-to-fly" as paying for a TR+line training. I mean, what is the difference? You are not getting paid to fly, and it is wrong. I stretched it far enough by paying for the FI-course myself, which after 1,5 years of instructing I have received about half the cost back. And that is one of the cheapest "pay-to-fly" schemes you can enter.
My plan is to live my life as it is right now, and don't worry about the future. I'll keep those licences current (cheap since I don't have a TR), and wait for the time where my graph of increasing flight time hits the graph of required total time of the airlines. If this happens by reduced requirement because of increased pilot demand or me hitting the current requirement, only time can tell
The airlines can afford to pay pilots what they deserve, we are just not giving them the opportunity to do so. First step must surely be to refuse pay-to-fly schemes?