In my experience (in the USA), it isn't the additional knowledge that limits your job opportunities but rather the attitude that seems to accompany the PhD. Many PhD's attempt to enter the workforce with a feeling of entitlement to greater pay and greater advancement opportunities because of their additional academic efforts. There are enough PhD's with this attitude that they have tarnished the whole PhD population and the ones who flaunt their degrees in the faces of their "lesser" colleagues have made it harder for the nice, pleasant PhD's to get fair consideration. Many of the PhD's I encounter in my line of work (software development) keep quiet about their degree and hold out their Masters degree more often as evidence of qualification for the work.
Generally, an advanced degree does help you get a higher starting pay and maybe starts at something just above entry level. But after that, in most work settings, it's all about what you can do. You won't advance any faster than your colleagues unless you are actually better at the work than they are.
Aside from the medical and sociological fields, where a PhD is specifically required, there are some non-academic areas of work that are structured similarly to academia, such as research departments or highly focused science-based work. These opportunities may only be available to those with adanced degrees.
You need to be clear about what your intentions are regarding the work opportunities you will pursue. A PhD is less likely to be an asset in landing a regular software development job. However, if your goal is to land a job that requires a combination of software development and physics expertise, you might be on the right track. You should investigate that job market, though, since it is likely very narrow, and therefore very competitive.