Peter, The three books on Dylan that I recall reading never mentioned that Dylan got his prolific writing and borrowing practices from Woody. However, your reasoning makes perfect sense. Dylan borrowed a lot of things and I'm not sure he ever returned them.

Andy Gill has selected interesting quotes for his book. (And it's the only one that I bought. The others were from the library.) Gill quotes Woody telling friends after Dylan played for him, "That boy's got a good voice. Maybe he won't make it in his writing, but he can really sing it."

Gill also quotes Tom Paxton recalling strolls late at night through Greenwich Village with Dylan as he scribbled away on scraps of paper. "His mind was on fire. Between the club and wherever he was heading, he'd start as many as five songs – and finish them!"