Starting in 2025, the Vera C. Rubin Observatory in Chile — funded by the National Science Foundation — will catalog the solar system from the ground...
"It took us 200 years to discover all the asteroids we know to date, about 1.2 million asteroids," Mario Jurić, the Rubin Observatory's solar system discovery team lead and the director of the University of Washington's DiRAC Institute, told Astronomy. "In the first three to six months of Rubin, we will double that."
That's one additional ground based observatory coming online in the Southern hemisphere. If we get our act together and build a lot more of these and other space based observatories we're going to see the true scope of the "shooting gallery". We really need to raise public awareness of this, as a planet based civilization we are taking our chances by ignoring the problem and assuming everything will be fine for a hundred or a thousand more years. All of our efforts at averting a climate catastrophe will be for naught if we get smoked by a rock big enough to fill the atmosphere with particulate matter and drop global temperatures for years afterward let alone anything bigger resulting in global firestorms and tsunamis.
Of those 1.2 million orbits, how many are dangerous?
Observing near earth objects (NEOs) requires shorter exposure times because their (apparent) motion is quite fast, and that has an impact on how faint the objects you can detect can be.
There are methods like synthetic tracking though, that can detect fainter objects (even those hidden in the noise, not visible by eye).