None of those large radio telescopes were ever really in the game of detecting near earth asteroids. For that large optical survey telescopes, such as PTF, ZTF,

None of those large radio telescopes were ever really in the game of detecting near earth asteroids. For that large optical survey telescopes, such as PTF, ZTF, PanSTARRS and the future LSST (and many more) are much more important. However for accurately measuring their position and velocity in 3D space radar measurements are extremely helpful (since they give you distance and radial velocity which those surveys can't give you). And for that Arecibo was quite a good tool in the toolbox, but not the only one. And the other telescopes used for this are in the 25m to 100m range (the Goldstone solar system radar has a 75m dish and 500kW X-band transmitter). In addition one doesn't have to use the same dish as transmitter and receiver (as long as both telescopes can observe the object at the same time obviously).