and there’s not enough people that want what you want
So you claim. We could hold a vote: „Should Apple have the exclusive power to decide what applications can be installed on iOS - or should applications be installable freely, such as on other OS (Windows, macOS, Linux).
It’s when a company uses a market advantage in one area to control an unrelated market
That’s the issue that will be regulated: application software markets have (for decades) been related but independent markets (from OS and hardware). And it has had hugely benefited innovation and pricing for customers.
Apple has chosen to bundle or „fuse“ hardware, OS and distribution of application software into one platform and control it all by themselves in monopolist fashion. That is obviously not illegal - but it should be.
People who own smartphones and have access to third party stores don’t use them. By a HUGE margin.
The fact that checks and balances aren’t needed for most users and situations doesn’t mean that they shouldn’t exist.Alternative methods of app distribution are checks and balances on Apple‘s behaviour and pricing.
Or creating incentives that make it more likely that companies would create more smartphone OS competition
Operating systems are a market that’s (basically) naturally converging onto few options.
When people or governments want and benefit from competition in the market for automotive vehicles, that doesn‘t mean that more mutually
incompatible underlying platforms should exist.
Have they attempted to curtail development of applications for other OS’s?
They have curtailed development of applications (and functionality within applications) for their own OS. Which, along with Google‘s Android constitutes a duopoly.