The problem is actually the same as crucibles problem.
1. No incentive to play really, since there’s almost no good loot and no meaningful progression. Especially for Gambit, as there is no adept version of the weapons.
2. It’s available for free to play players, and therefore does not generate the money needed for it to be worth developing.
Just put both behind a $5-10 paywall and then give us new maps and rewards.