I know for a fact that there's at least one company (that I can't name) that offers what I would call "Addiction as a Service".

Their system allows to create n-dimensional currency systems (coins, diamonds, etc), currency conversion rules, collectible management, in-game stores with their schedules, crafting/merging logic, probability distributions (including "dark distributions" like OP's link) and even prices (for profitability hints/warnings). Basically everything a fleecing game needs. They even offer templates inspired in famous games to get you started and tune as you go.

They charge quite a bit, but the "foundational app" upfront cost is much lower: it's limited to UI and a relatively thin business logic that targets their API endpoint (mostly mapping API ids to in-game assets and use or server-side logic).