Generic C1 Future Inextendibility Near Rotating Subextremal Kerr Spacetimes

For each fixed Kerr spacetime with mass M > 0 and rotation $0<\mathfrak{a}<M$, we prove that a dense G${}_{\delta }$ set of nearby smooth, complete two-ended vacuum data has a maximal globally hyperbolic development with no future C${}^1$ extension. The neighborhood and genericity are defined in a weighted smooth topology, and ambient extensions may be nonvacuum.