Absolutely agree, Mr Zilch. If my covers band decides to add a new number to the set, there’s unlikely to be any sheet music available, but a version of the essential chord charts are usually available onlIne as a starting point, as are the words. The skill of non classical musicians like us is to hear the whole number, deconstruct it into the various parts using whatever tools (including our ears!) we have, then rebuild it as an exact copy or an interpretation as suits our purposes. Post-modern Jukebox are masters at the latter!
Funny thing is, although classical instrumentalists are superb technicians at reading parts and masters of their instruments, not many of them can or want to play by ear, busk or do the decon-reconstruct tricks that the rest of us do. My dad was a concert violinist, but could never get his head around a 12 bar blues...