For me the question is:
why do I prefer to listen to old hits, period. :P
TBH, I listen to the Beatles, Elvis and old Charlie Christian on my studio monitors all the time, and I don't think I enjoy them any less. Obviously, that set-up is quite flat. But that's how I like music.
That being said, there's obviously some kind of knee jerk reaction upon hearing those old albums the way I used to hear them, on a cheap turntable or even AM radio. Warm and fuzzy feeling all around.
I heard Hound Dog yesterday at Home Goods, and my mood sensibly switched. I went from impatient/anxious to be done running errands to just enjoying myself. In a similar situation, a hit from the last 10-15 years would have me boiling... The poor quality speakers would have rendered things worst, if at all possible.
Though, come to think of it, maybe not. Putting up with the excessive bass and high frequencies requires yet more mental energy.
Modern mixes and modern aesthetics, both auditive and visual, are basically, more often than not, a relentless agression on the senses as far as I'm concerned. It's like they filter out the essential to be able to bring you more of what should be mere dressing... I guess audio equipment is designed to allow just that, too.