> Courts do not require a literal monopoly before applying rules for single firm conduct; that term is used as shorthand for a firm with significant and durable market power
I'd say Amazon has "significant and durable market power"
Especially because the first part of determining marketshare and market power is determining the market. New markets happen all the time, with old markets dying out. Twenty years ago, smartphones wouldn't have been a market. Fifteen years ago: streaming services.
Like going back to your "Intel with x86", what is the market? x86_64 CPUs? Sure they have monopoly power. All CPUs? Now they don't have as much because they're competing with ARM too. Mobile phone CPUs? I don't think there's been a new Intel phone since the Asus Zenfone 2 (2015).
article - https://www.ftc.gov/news-events/news/press-releases/2022/11/...
They are more rigorously enforcing laws against unfair practices, monopoly or not.
"Unfair methods of competition, the policy statement explains, are tactics that seek to gain an advantage while avoiding competing on the merits, and that tend to reduce competition in the market."
The unreasonable part is where the monopoly power comes in.
Companies lessening competition happens all the time, it’s the monopoly aspect that triggers antitrust.