Interesting how the immediate reaction is “postgres does not scale” when there is a single table lacking an index.
This also tells how important competence and knowledge of the system is. People that came in new and didn’t know the system like you do probably lacked the confidence/skills to just “get in” like that.
Yeah, I think though what happened in this scenario probably happens a lot everywhere else also. In my entire career, this type of scenario is very typical. Lots of Meetings / discussions, standups and talking uselessly without jumping in face to face with the actual problem. Things get in the way of the science and facts. Which is why it's important to remove fear, think from first principles and break things down and get your hands dirty.
This also tells how important competence and knowledge of the system is. People that came in new and didn’t know the system like you do probably lacked the confidence/skills to just “get in” like that.