Should I get a CS PhD if I'm only interested in industry research? I'm currently working on a masters in CS and working at a university as research faculty (my title is 'research engineer'). I'm in the branch that does mostly contract work with the government or private industry, so not academic research.

My employer offers an attractive proposition for getting a PhD. I would keep my current position and salary in exchange for doing a project relevant to the division. They also provide a year of PTO to work full-time on the dissertation and time during the day to go to class. My work is mainly robotics software so I think it would be feasible to find a sufficiently related topic of research. As a university employee I get an indefinite tuition waiver so I would not need to do any teaching or research outside of my normal work.

My goal for the PhD would be to work in industry research, along the lines of Waymo, OpenAI, along with lower-tier companies. My impression is that there are many more of these jobs than academic positions, so I have I more reasonable chance of success.

Given the appealing financial circumstances, is getting a PhD an obvious choice? Should I just finish with the MS and try to get industry research jobs right away? Is my impression of the state of industry research correct?
Having a PhD or other Research Doctorate will definitely help you with many large companies. At some companies there is a fairly large gap between what someone with a degree can do and earn and someone without. "Senior Scientist" may only be open to PhD holders for example. 

Moreover, some companies really need people on the cutting edge of research. Think Alphabet/Google here and similar data and algorithm driven places. 

But I'm speaking of large and established companies. IBM, Bell Labs, and such. It may not be quite as valuable with newer companies and probably not at all with startups. But, large companies can support large scale research that may take a while to mature. They can offer a stability of employment similar to that available in an academic position.