I think it was Noel Gallagher who said good musicians borrow, great musicians steal.
Been going on for years, George Harrison " my Sweet lord" the Chiffons " He's so fine".
At the end of the day there are only so many notes, chords and progressions, mathematically there are bound to be replications.
Much of this is driven by the lawyers, if I owned the rights to a popular song and someone rang me up asking if I would like another million, no win no fee, I would take their arm off.
I imagine se people are doing this full time now, computer programs designed to look for similarities.