The ground plane can have a massive
effect on ability to receive. An antenna
system doesn't really care if it's used for transmitting or receiving -- it has gain and pattern and impedance, regardless. An antenna system that requires a groundplane (or ground, anyway) needs that ground to work. A lossy or un-matched ground will reduce the antenna efficiency.
What is true is that most receivers have more than sufficient gain, and the background atmospheric noise is strong enough that even an inefficient antenna will usually work well enough. But if the antenna is bad enough it can make reception very difficult (unplug the coax from your radio
in a coathanger instead -- see what happens).
(I won't throw my credentials at you, but they are more than adequate)