Perhaps there is some sort of pressure by stockholders to have the ability to promote their own products and services on the device or just some sort of backroom dealings.
My personal hope is that Apple course corrects at some point that they do not need to extract the extra cash while damaging the customer experience. The company feels much less customer oriented now and has lost a lot of the premium feel. I have already stopped using their TV app because they have made it nearly non-functional with the amount of promoted content. The News app has an exceptional number of subscription only items in the feed to where I am about to go back to pure RSS. The feeling is like what Google would have done with Google Reader if it was still going stuffing in promotions.
I agree first party apps should be advertisement free if they are advertised as being included in the price of the phone. Otherwise it is a hidden bill you are paying with hours or days of your life that you can't get back.
I would pay for a service that just disabled all first party promotions advertisements. Give me the real price instead of wasting my valuable time with advertisements I would never click.