Yes, if it’s ** Pat Boone ** ripping off ** Fats Domino ** or any of the other white artists who covered R&B songs in the 50s, reducing the potential pool of record buyers.
OTOH, in the late 40s and early 50s everybody covered everyone else’s material. In my Joel Whitburn’s * Top Pop Singles 1940-1955 * we find that Patti Page may have had hit with The Tennessee Waltz in late 1950, but it was also recorded (and charted) by the Fontane Sisters, Guy Lombardo, Anita O’Day, Jo Stafford, Guy Lombardo and Spike Jones and his City Slickers.
Rock has a way of mining its own past, with mixed results. I still get a big kick out of Frijid Pink’s high energy heavy-fuzz version of The Animals’ ** House of the Rising Sun ** which in turn was taken from who knows how many blues musicians. Heck, the Sixties even mined the recent Fifties (think Blue Cheer doing Eddie Cochran’s ** Summertime Blues **)
Also have to mention the habit of artists covering * themselves ** by releasing endless live versions or remixes of studio songs. For good examples, think Neil Sedaka’s re-invention of ** Breaking Up is Hard to Do ** as a slow ballad, and a similar unplugged effort by Clapton on the immortal ** Layla **