Does that mean that if I smoke some drugs I, too, can write like Shakespeare?

No, but if true it might suggest that, if you can write like Shakespeare, you can smoke dope and still write like Shakespeare.

Since it appears they were smoking grass back then, why the hell did tobacco catch on instead? We've always been told that nobody in the Old World smoked anything until they got the idea from America, so assuming that's true (bit is it?), to explain traces of cannabis in a pipe in Stratford somebody in must have picked up on this new fashion, and decided to experiment with something locally grown and cheap, instead of this foul smelling pricey stuff they were importing. So how come after that anyone bothered with tobacco?