PhD in CS or continue working

[notreallysure]

I've been working in industry for many years, but I've developed an interest in research over the last couple of years. It's not directly related to my day-to-day job, but I've been doing some research on nights and weekends the past two years and produced some interesting (imo) work. I realized at some point I wanted to do research full time and decided last fall to apply for PhD programs just to test the waters. I (somehow miraculously) got accepted into a program with a professor that is doing really great work in the field.

My dilemma is that I would be taking about a 10x reduction in salary. I have a wife and two kids and am the sole breadwinner of the family. I knew this when I applied, but decided to punt the decision to a later date if I actually were to get an admit. I actually have saved enough money over the years that I don't think I would really run into any financial trouble where I couldn't provide for my family, but I would also be eating away into my savings. My wife has also said she plans to go back to work in a couple of years (this was independent of me doing a PhD) and after modeling it out a bit, we would definitely still be able to live comfortably for the ~6 or more years it would take me to finish the degree, but obviously not as comfortably as if I just continued working.

I don't hate my job, but my interests have shifted and my heart's not into the work anymore. I also feel my skills are becoming stale and at some point will become less valuable if I don't make a change. The field is very hot right now, but who knows what's going to happen in 6 years. Assuming things stay the same, after graduating with this PhD, if I decide to go into industrial research (which seems the most likely at my age), the salary would be on par with my current salary. I've also considered applying directly to these research positions right now, but it seems unlikely I would get through the process without a PhD or at least a research-based MS.

I understand this is a bit of a unique situation, but just wanted to gather my thoughts and vent a bit in case anyone has been in a similar position.