I guess what I really want to say is that; I have found
through 35 years of fooling with stereo, PA, playing bass,
recording and listening to the best equipment I could get my
ears in front of, listening in an acoustically optimized
listening environment is essential to hearing what is in the
recording. That being said, the reverb (natural or added) in
recordings, being low level in nature and most audible when
the music program stops, is the first sonic component to
become masked by the reproduction rooms own sound.

Unless the room is unusually -- or pathologically -- reverberant, this is
not so. The average room's decay time is considerably shorter than the
reverb time of most recordings, and is incapable of masking it.

The improvement you hear is to better imaging, and the resulting ability to
better appreciate the recording's ambience.