However, let's do some rough numbers. It says they had 3 product managers. I would guess this means 8-10 engineers. 3 QA folks would be a decent enough ratio. You've then got a GM, a head of product, head of UX, head of data science, head of BD, editorial lead, and head of engineering who all just left. We're up to 26 people already. Now we've got some HR staff, maybe a recruiter or two, finance team, people underneath the UX, editorial, data science and BD teams (let's generously assume 1-2 hires each), and we're over 40 people easily. We haven't even discussed marketing, help centre and customer support, a DBA, ops, or IT support.
Does that all make sense now? It's a company within Twitter and there are a lot of specialized roles to keep something with 25-30 million active users a month running smoothly. I'm not then going to go into what each person does each day, but with a product that you're trying to drive growth and new features for, while supporting existing customers, and just generally running a company, that takes a lot of bodies if you want to do it effectively and not cut corners.