not really disappointing because you're right, PC players have learned not to expect these features at this point. MCC on xbox also has HDR, but there is no HDR on PC.
microsoft continues to claim PC is an important ecosystem and that they haven't forgotten PC. so far it's only talk, because they put features like splitscreen and HDR on xbox but not on PC. if they are really committed to PC as a platform then they wouldn't do such things. all it does is leave PC players feeling shafted.
Eh, If we're being real we can also admit the amount of people that use splitscreen on PC is a fraction of a fraction.