Not always true, though. Any strain grown shittily will make a shwag plant, or at least what I've seen. It tends to depend more on how it's grown than the strain. With that said, if two strains are grown really well, of course one is gonna be better.
Agreed about one being better, but even a realy badly done white widow (if atleast attempted with the right setup) should still be relativly dank. I couldnt see it being schwagg level at all... not unless she's growing a male in the same room and it polinates the females (greatly cuts THC)... and then usualy when you get schwag its in a brick which has usualy alot of THC already been somewhat rubbed off, whether someone sifted the buds for hash or just from being pressed together and stuffed in endless bags/boxes/bales/dryersheets ect ect... Schwagg usualy starts off as good weed, its just handled badly and by ALOT of hands usualy. Thats just my $.02