Contrary, I'd say the content is more important than the recording quality.
So you like Elvis, and the recording quality back then was limited by the type of equipment used in the 50s/60s. No matter what fancy digital mastering techniques, they can only do so much.
And now, your playback equipment is high end enough to bring Elvis "back to life" and appears he's singing in front of you. That doesn't change the fact the recording was really not up to today's standard, but who cares? Your toes are tapping!
Enjoy the good music and not worry too much about the logic or technicalities.