[ponyous]

Is there any incentive you know that tries to standardise how desktop apps should behave?

Just my observations & opinions: I don't think we will reach a point anytime soon where desktop apps have standardised UIs much more than now. The most effort in this space is done on iOS. Apple pushed UX Guidelines quite hard, most of the apps are mainstream consumer oriented and are not even that complex so Tab bar on the bottom + screens above works well. Desktop apps are generally much more complex and therefore harder to standardise I guess.