I would love an astronomer to figure out how far away our solar system could be detected using our best equipment. The first planet detected would be Jupiter, but would its 12 year revolution period be too slow to provide a Doppler shift to the sun’s light?
The capabilities of current equipment have been enhanced, but also used in new ways to improve detection; newer stuff has improved detection; orbiting observatories have been, and will continue to be used to extend reach. Analogously, when SETI listening began about 50 years ago, it was calculated that the strongest then-extant radio transmitter could be picked up by the strongest then-extant receiver at a distance of something more than ten light years, which restricted the number of targets. Within just a few years the sensitivity improved to extend that range fourfold, which was, what, 64-fold increase in the volume of space.