Why does it have to be Shakespeare? There are millions of good writers that got there by working hard. Seems pointless to go into either extreme, when just being good at anything is generally hard.

It doesn't have to be Shakespeare, but hopefully everybody agrees that writing at Shakespeare's level is indeed hard. I agree that writing good (but not great) or even just ok literature is still hard, but that invites a bunch of no-true-scotsman arguments that I just can't be bothered dealing with (like "writing Fifty Shades of Grey isn't actually hard" or something similar).