> There are more than two platforms out there
Such as? If I'm making a mobile game, what other phones can I realistically target other than Android and iPhone? You don't really think that the Librem 5 is a real competitor right now in this space, do you?
> because mere quantity of stuff out there is never a justification for taking it over
All of US antitrust law is based on the idea that the quantity of providers in a market matters. If you're arguing that we should get rid of antitrust entirely, fine. But be upfront about that, that's not a mainstream position to take.
> no monopoly exists without a government acting as a gatekeeper
I'm not going to derail things too much here, but I do have at least a few Libertarian bones inside of me. To the extent that I am sympathetic to your argument here, I would question why you think that Apple is different.
Apple's dominant market position exists in no small part based on its exploitation of copyright, the DMCA, import laws, and heavy lawsuits over trademark and cross-compatible app runtimes, all of which only work because of artificial government intervention into the market.
If you want to go full Libertarian, I'm not necessarily opposed to the idea, but then I'm also going to go full Libertarian and ask what your views are on abolishing copyright. Apple might not have such a stranglehold over the market if it was legal for other US companies to build iPhone emulators, hackintoshes, to distribute jailbreaks, and to build their own compatible phones that could run both iOS apps and apps from other markets.
If we're all OK with making that stuff legal, then I'm OK with dropping antitrust. If we're not OK with making that stuff legal, then I'm keeping antitrust. I'm OK with either having government regulation or not having it, but no halvsies.