> miss the reentry cone and skip off the atmosphere into space?

My layman understanding is that this was never an option even for the Apollo trips from the moon - the problem was that a wrong re-entry angle wouldn't slow the capsule down enough to bring it down to the surface, and it would have to orbit several more times before finally slowing down enough to return.

This was a problem for two reasons: (1) the landing site would be unpredictable, and it wouldn't really do to land on the Kremlin, or in the middle of the Sahara, or in the middle of the Pacific. (2) The capsules didn't have enough supplies to keep the astronauts alive for too long, and too many orbits would mean that they'd be dead on arrival.