Do PhDs have any advantage in growing up the career ladder or is it a total waste of time?
You would if you worked at places where they solved new, complex problems, but not where they hire by the truckloads and don't have specific jobs in mind for you at interview time.
I have consistently seen PhDs (US only !!) respected above the rest. It matters.
I spent 6 years working very hard while earning $30k/yr and added 0 YoE by industry standards. It is a TERRIBLE choice for ladder climbing. At the same time I have no regrets because that's not what drove my descions.
Zero. And I was in ML, in Google research and am in FB research now. If you’re only optimizing for ladder climbing it’s going to cost you more than it would help.
Do you have PhD? Are/were you Research Scientist or Research SWE?
Maybe for ladder climbing -- but you don't see many non-PhDs in research positions