Is doing a mid-career PhD worth it?
The MA glass ceiling is real.

I can't talk specifically to the situation at a Canadian technical college, but the same thing happens in the DC policy world I work in.  A lot of think tanks and policy shops have researchers with years of experience who can't get promoted above a certain point that is practically entry level for incoming PhDs.  Some places are starting to address this, recognizing that a PhD is not better than years of successful research experience, but it's still a wide-spread phenomenon.

So, I wouldn't be at all surprised to find out you don't have any recourse.  If anything it's likely to be a harder ceiling since you're actually at an academic institution.  

As for whether taking the time off to do a PhD is worth it, which I think is the root of your question?  That's hard to answer.  You could run down some hypothetical bullet points:


If I did the PhD, and then got the SAME job at the same pay after, would it still be worth it?  That is, would the accomplishment on its own be gratifying?
If I did the PhD, and then got a better job but no more money, would it still be worth it?  That is, would getting through that glass ceiling be enough of a motivator?
How much more money would I expect to make after my PhD, and how much money would I be giving up by leaving the job market for 4-6 years, and would I be coming out ahead?  Also account for whether you can get funding for your PhD or would have to self-fund it all.  In other words, the pure economics of it (you say it would be a financial burden, but that's not necessarily so in the long run).
All other things aside, am I willing to make the sacrifices necessary?  You would likely have to temporarily give up lots of things to do this, like having disposable income and the ability to relax on nights and weekends.  If you have a family that can be a hard adjustment, though lots of people do it, myself included.


Good luck!  My overarching piece of advice would be that if you're not passionate for the subject you shouldn't do a PhD in it.  But if you can tick that box off, the rest is up to your preferences.