> watch while the neutron star converts to a black hole where, as usually proposed, the mass that was the neutron star suddenly shrinks to the "singularity" at the center of the black hole.
This "conversion" doesn't imply matter transitioning from one state to another. The main thing happening during transition to a black hole is that the light can't escape anymore - you see the star in one moment, and can't see it in another moment. Not necessarily because of some matter transition, but because it stops radiating light.
Singularity is a mathematical artifact, we don't know what's happening in the blackhole with matter and don't really care since it has no effect on the outside world.
This "conversion" doesn't imply matter transitioning from one state to another. The main thing happening during transition to a black hole is that the light can't escape anymore - you see the star in one moment, and can't see it in another moment. Not necessarily because of some matter transition, but because it stops radiating light.
Singularity is a mathematical artifact, we don't know what's happening in the blackhole with matter and don't really care since it has no effect on the outside world.