Apple uses their own technology to make their products better. That’s not a scandal. Their products aren’t the most dominant in streaming, maps, or payment. Most of the complaints are about what they aren’t doing (going out of their way to make proprietary features available to 3ps), not what they are doing (say: giving themselves special push notification permissions). So what influence are they exerting exactly? Why is it so pernicious?
They're exerting the same influence that Google did over their Android partners. They created a faux-open market with arbitrary rules that ensure their products always win. Google lost their case because of this and Apple should too.
Google lost their case because, among other things, they offered back room deals which favored a blessed few and were not available to all. E.g. you could not get the rate Spotify was getting charged for in app purchases (zero%).
The DOJ's 90 page lawsuit is a lot of things, but precise or even factual it is not. For example, it doesn't even cite the selling price or terms of the original iPhone correctly (off by almost 2x) and invents vague terms like "the performance smartphone market."
You didn’t ask “what was the price of the original iPhone”. Your questions were…
> So what influence are they exerting exactly? Why is it so pernicious?
Which are both answered in the document.
Almost the entire document is defining the performance smartphone market. It’s mentioned in the document 88 times. The definition isn’t “phones over $400” because it’s defined by the market forces that Apple creates - there’s a feedback loop