Crown Crates is one of the ways they get the most income and you want them to give everyone a guaranteed Legendary item every month? For free?
A lot of people complains the game is full of "casuals", and casuals play casually, not regularly with dedication.
On Xbox platform last time I checked 0.04% of players had completed the Firesong DLC - 6 months after a launch that gave it away for free.