[acdha]

> - Dropbox spends $200K/year (salary, benefits, equipment, SaaS, etc.) for their average infrastructure engineer

The usual rule of thumb is that you assume 2:1 for salary and support costs — that starts to drift at the higher end of the pay scale but I'd doubt that a company in San Francisco isn't paying a substantial amount for office space, health insurance, etc.

Your general point is still correct: call it a hundred engineers to break-even and it's likely still a substantial win, and there are some interesting angles for additional cost-optimization given Dropbox's mix of high network traffic and long-tail storage.