The process is much more about using another idea as inspiration and a starting point. It's a way to get out of a rut. You'll almost never end up with anything like your starting point.
I've always assumed that this is what the quote is referencing rather than taking actual elements in full as is the case in a few of these examples.
I wouldn't be surprised it Picasso hadn't ever said it at all. Even if he had, Picasso created his own genre of art. Actions speak louder than words.
It really doesn't matter where the quote came from. Even when put into proper context (which has rarely happened in the past) the logic behind it is shaky.
Great artists do imitate, as students they copy the techniques and methods of those who came before them, in order to learn and master the skills they will need to make their own art. When they are ready, the truly great artists then proceed to create things that we've never seen before.
In the context of Music, which I understand better than the visual arts, imitation is what a young composer or musician will do. Once they develop their own voice, 'stealing' becomes a thing of great skill: remixing, as it were. In Stravinsky's case, he lifted content from Webern and made it new. Bartok did it with Shostakovich who did it in turn to Tchaikovsky and on and on and circularly.. one of the wonders of studying musical history is tracing the influences, and the mastery of those who took what came before them and made it new.
That one?