[t3nary]

How difficult is it to get into a position at a top company where you can do ML research, without having a PhD?

And I'm also wondering about going back to university: Is it difficult to get into a good ML PhD program if you've been in the industry for some years?

[achompas]

Very difficult, at east for research. Top companies with ML research labs (FB, Google, Uber) are basically externalized academic labs. The heads of these labs are simply bringing talent over from their former departments (NYU, Cambridge/UBC, CMU).

It is not impossible to work at these labs as an engineer without a PhD, but I don't have a deep understanding of these roles.