Wrong on almost every account here.
The deal was struck between Universal and Netflix back in early 2021. Less than a year after Peacock launched as Netflix was already licensing Universal Illumination and Dreamworks films. This is why you have Camp Cretaceous, Trolls, Kung Fu Panda and others raising kids the modern way Saturday morning cartoons and Disney Afternoon extensions of properties used to.
The difference is, most of Universal's movies are performing very well in theaters and profiting long before their Peacock and Netflix Reach, which combined is comparable and more profitable than just Disney Plus' as Universal collects the licensing fees as other platforms show them with ads. Which in turns makes those platforms want to show those films too as they were already hits. The Universal films tend to be on Netflix's Most watched ratings list after they move to Netflix from Peacock. Which by the way, is at most four months for the massive hits like Mario from Peacock to Netflix, but there are plenty who go only about 40 days from one service to the other.
The last part of your post points how how things are changing to this. It is something Disney is now trying to do because their movies are not doing well in theaters, and they like making as much more more money than their competition.