No, you're oversimplifying a lot. Just security and infrastructure operating at Asana's scale requires several dozen engineers. Additionally, Asana has been developing all sorts of features around working with "tickets" - Gantt charts, automation, 3rd party APIs, mobile apps, etc. All of this while working with a large legacy codebase that makes development slow.

(Note: I worked at Asana when it was ~100-150 engineers, and it felt like we could use double that. Having since moved to a FB team, I find I can develop UI features at probably 3-4x the speed in comparison to my time working on Asana UI, simply due to using modern React code with jsx and functional components using hooks)