Disclaimer: I have a Ph.D. degree, and I work in machine learning. Having said that, I think other than becoming an academic, you don't need a Ph.D. degree to work in any field. Getting a Ph.D. degree helps you develop certain research skills, but
- You don't need those research skills for most jobs.
- You can acquire those skills without getting a Ph.D. degree.
Martin Wolf, the chief economic correspondent for the Financial Times, doesn't have a Ph.D. degree (he has a Master's degree), but his word carries a lot more weight than most Ph.D. graduates. I think to succeed in any field (including machine learning), you'llyou have to know how to learn and think thorough stuff on your own. A Ph.D. degree will help you practice those skills, but it's not an end to itself. Anyone who isn't willing to interview you just because you don't have a Ph.D. degree, is probably not worth working for anyway.