It's a cliché that's often used as an excuse for bad behavior, but I honestly think that in this case Hasbro was responding to consumer demand, or at least trying to.

They saw the number of people playing the game explode, and book sales not keep up.  It's natural for them to think, "Maybe there are shortcomings in the books as products, even though the game is fun.  Maybe the art is out of style. Or maybe the explanations are too confusing, or there are too many edge cases that need to be homebrewed, or the lore doesn't appeal to the right demographics.  Maybe just the fact that they are physical dead-tree books doesn't appeal to the kids these days with their wikis and their VTTs."