I didn't mean to imply it needed to be _graduate_ research - however it would be news to me if they were publishing at top conferences independently of a lab or research branch at a company.
I didn't said they were publishing independently, just they did not had any academic research experience. e.g. in FAANG, it's not hard to get into teams which publishes ML papers. Also, I know one guy who contacted one professor, and they collaborated and published few papers while doing full time engineering job.
How do the people you know go about it?