While some games do, the few that do those odds are not predominantly displayed nor they are externally validated as being accurate.

There is also no disclosure as to if the odds are manipulated on a per player basis, which I believe there are a few patents related to changing the "drop" rate based on player behavior, this is similar and can be combined with your comment about monitoring to drop a discount at the right time

In the context of Diablo, I can not find the Odds of their loot boxes anywhere published.