The different rates are reflected in the burnout, low pay, bankruptcy and failure - or the opposite - of the developers who launch on them.
Right now for example its basically impossible to make a reliable income just from PC, for the average solo developer or micro-studio, due to the insanely high 30% commission taken by Steam.
Its necessary to launch cross-platform onto consoles, and optimizing the graphics and control schemes for these devices means that PC is not the focus.
Steam charges 20-30% depending on how big you are, and probably has a sweatheart deal with EA.
Xbox and Playstation offer subsidised hardware and arguably have a 0% rate given that so many titles are published in-house.
Nintendo offers an effective 25% rate as 5% of spend is rebated to customers' wallets.
Microsoft charges 12%
Epic charges 12%