Is my Ph.D. research topic worthy?
At some point, if you are to have an academic career, and maybe any career, you are going to have to separate yourself from this advisor. I question his ethics, actually, in keeping you so close to something from which he benefits outside academia. 

If you state correctly that he is only letting you work on less consequential aspects, I doubt that he will offer you great support in the future. This seems like a double dead end. 

But quitting seems like it would be too extreme a step, also cutting off your future career. 

My suggestion would be to explore, quietly, with other faculty, whether you can work with them on a dissertation, perhaps cutting ties with your current advisor or perhaps working jointly on another project that is unrelated, or at least less related, to the current advisor's company. 

It is important to keep your search a bit quiet, if possible, though you can explain your reasoning to other professors, I think. I would first look within your current institution, and if nothing is available, start an external search for an advisor. It may be possible to enter another program as an advanced student, skipping some/many of the requirements that you have already fulfilled. 

There isn't much in doctoral study than having an incompatible or somehow unhelpful advisor. You can, I hope, solve that problem without quitting your studies altogether.