I don't have any experience with large-scale sites either, but here's my view:
It is a function of complexity, but complexity is often necessitated by scale. More users means more problems with scale, which leads to increased complexity to address the problems, which leads to a larger team needed to maintain the software.
That being said, 50 engineers seems enough to me for maintenance.
It is a function of complexity, but complexity is often necessitated by scale. More users means more problems with scale, which leads to increased complexity to address the problems, which leads to a larger team needed to maintain the software.
That being said, 50 engineers seems enough to me for maintenance.