I was on the Docs team 15 years ago. The rewrite (from Writely to the new OT-based editor) had just launched. We were facing an enormous list of features we lacked that prevented enterprises (and some consumers) from using us. I think we didn't even have inherited text styles at that point. Markdown was so far down the list compared to absolute basic editor functionality. Plus there were some reasonable arguments against it, like "the 'spec' is some guy's webpage" The thing that stopped it for the next 5 years (which was how long I was on the team) was that the Word <-> Docs conversion service was a separate team based in Sydney called Changeling. Having literally opposite work hours made it difficult to coordinate with them, plus it made it easy for the I-don't-want-Markdown-in-Google-Docs crowd to just say "obviously Markdown conversion should be handled by this other team that's really difficult to coordinate with," which was a really effective way to shut it down in favor of things that would better help them game promotion. I don't have any insight into why they finally started prioritizing it a few years ago, but my guess is that they started losing contracts to Notion which is a lot more Markdown-native