The fact is, what we grew up hearing was actually manipulated. The Sun Records stuff had reverb added that we got used to hearing. Now that we are actually hearing what was on the real tape before RCA messed with it, sometimes it's odd. I understand what you are saying. However, what we are hearing now is actually what those Sun Records REALLY sounded like before RCA got them.
In addition a lot of the stuff in the 50's we grew up hearing reissues of on vinyl that were reprocessed which was basically just having the original track in one speaker and the other speaker being on a slight delay or having a reverb added...just something to make it different which gave the illusion of stereo.
Again, this is not how the stuff was intended to be heard.