I worked for MSR for ~7 years and all of the papers I worked on were in LaTeX, all the papers I saw from my colleagues were written in LaTeX as well. The only people who wrote papers in Word were from academic communities where that already happened often (e.g. lots of Word papers in HCI conferences; I was in the PL and OS communities where it was very rare to see papers written in Word).

But yes, a paper written in MS Word is glaring by how it handles kerning and hyphenation. You'd be surprised how much products teams don't care about type setting (and Google Docs at Google where I work now is about the same).