That's crap... The whole PIC requirement is absurd given that at least our airline system is all strict seniority based...It's a flawed logic as it doesn't look at the overall picture.
It's not "crap." What you lack are the basic qualifications, and that's exactly what's been said here; you need to hold the basic qualifications in order to upgrade. Period. I believe I said that in a post above.
Upgrade is based upon seniority, dependent upon being qualified to upgrade. Merely being in the seat doesn't necessarily mean you're able, as you've shown in your post. You're angry, justifiably so...you saw what you thought was the brass ring, you grabbed it, and you discovered avaition where the only constant is change. The problem was that when you grabbed the ring, you lacked the qualifications...you ran before you could walk, and now you're angry about not having enough walking experience.
Perhaps more significant is that you feel going somewhere else to gain PIC experience is a step backward. That's unfortunate. One mans ceiling is another man's floor, some say. I see people daily who can't afford to eat, many who live in tents in the desert and carry water for miles in goatskin bags, and whom will never have a small percentage of what you have or be where you are...your ceiling is already much higher than theirs.
You're not the only pilot unable to move up because of lack of qualification, change in circumstance, or hollow promise. It's rife in the industry. The best defense against that, if there is such a thing, is to seek out as much qualification as you can get...in the context of this thread, that means getting as much PIC experience as you can in aircraft appropriate to what you seek. If you seek a turbine position, then turbine PIC...if you seek a multi turbine position then multi turbine PIC. You get the picture.
I'm sorry to hear of your circumstance. It's not uncommon. Many of us have been there. Job security in this business was always an illousion...some are having an uncomfortable night as they wake up to that fact in this modern day and age. Best of luck.