And yet the narrow-field Hubble produced this famous image

https://science.nasa.gov/mission/hubble/science/universe-unc...

Those are galaxies. In a field of view "about 1/13th the diameter of the full Moon."

Your point being?

Hubble in certain circumstances can see narrow and far. If you express this as a cone, you can extrapolate a volume.

It might be very useful to have something that can search wide and maybe not as far; nearer Earth dangers perhaps. Express that as a wider cone and extrapolate volume.