Can confirm, buddy with a resin printer is slowly hooking me up with an Adeptus Mechanicus army and he prints shit for his friends too. Recasts are likely in-between price-wise but pretty solid quality.

Money. 6-axis isn’t cheap to run or maintain, especially at this scale with the desired precision. Add in the inherent issues of working with a variety of paint colors (especially aerosolized), subtract the ability to mask features from over spray. Their prices would have to make Warhammer look bargain bin in order to recoup the costs of the machine, maintenance and consumables.