Sounds like you have thought this through.
Unfortunately, it also sounds like you have been seduced to the Dark Side. Forever will it dominate your destiny.
Getting a PhD because you just wanna get one is probably the best reason.
Best of luck with your decision. It will be a long and arduous path, but one that you can be proud of completing.
My comment about the promotion/hiring boards was geared at you finding out what these boards are truly looking for when they make their promotion or hiring decisions. Not every industry has such boards, yours may not.
The point was that if you are considering getting a PhD to get promoted, first find out if getting a PhD will actually help you get promoted. The same with wanting to get a PhD to get hired to another position.
You don't want to go through the trauma of getting a PhD only to find that it will have a minimal influence on your future plans.
Serious advice: If you know of any PhDs in your industry, seek them out and talk to them. Not all PhDs are bitter cynical buttheads like I am.
Each industry is different as are PhD programs. You don't want to get "a" PhD, you want to get "the" PhD that will help you the most.