People who say this have never worked in an enterprise, global software company. Or if they did, they may not be working on key projects.

Just SCALE ALONE is enough to expand a group of engineers a significant amount. A personal project is fine to run 1 AWS or Digital Ocean instance to run the application, database. But global distribution that has to support tens of thousands, hundreds of thousands, or even million+ users concurrently globally? It's a big orchestration of applications and services that requires much larger teams.

Add in payment services and managing those integrations. Then, given that you're a global company and have to operate in multiple countries you have all sorts of regulatory compliance requirements. Who oversees that? Who manages all of these requirements? Not a single dev or a small team.