The EU and their dwarfed tech sector because they’ve made a regulatory environment hostile to business.
This argument boils down to “does the maintainer of a platform have the right to maintain their controlling interest in their own platform if that platform itself is not a monopoly” and I’d argue the answer to that is a firm absolutely.
If I’m raising sheep on my farm it isn’t my duty to provide my land to my neighbor to also raise sheep.
It's more like you providing land to raise sheep, but put your nephew's sheep in the best spots, pushing your customers' sheep where they can't eat so well. So your customer will rightfully complain that you're hurting their business.
High cost for web apps to support iPhone users who expect an app like experience. Android on the other hand makes this very easy in comparison.
Try asking your apps iphone users to go to the share button on safari to install the app.
This is the wrong analogy. If you want to use the feudalism analogy (which I always find appropriate for antitrust discussions), Apple is the Ducal landlord and also owns several farms that compete with their tenants.
Now, in medieval England, you would be right that the landlord has every right to do this. In the modern United States of America, antitrust laws are specifically written to avoid this arrangement. That there is another farm is irrelevant - we have laws to keep the power of landlords in check as a matter of governing philosophy.
For the last 50 years, a pro-consolidation school of thought has formed that specifically precludes enforcement of the laws, but the laws are still on the books that specifically aim to prevent an incestuous relationship between producers and distributors. In Apple's case, they have bundled the App Store and OS in a way that allows them to make the rules of the market and precludes a reasonable degree of competition in a major sector of the economy - it's an obvious target for competent law enforcement to take this type of action.
I don’t think we can look at EU and point at a single thing and say that’s why they have a smaller tech sector. Heck, here’s a random argument I can throw out of nowhere for it: they are far less migrant friendly.
The government is arguing they have violated the laws, that's the entire point of a lawsuit. Apple has become a private regulator in the mobile app space, and the government is correct to break this power.
> I think dangerous to the market because you’ll stifle companies wanting to try new things for fear of someone attacking them for success.
This is the corporate equivalent of "Oh won't someone pleeeeeeeease think of the children". Give me one example where innovation was stifled because of antitrust action. It almost always goes the other way - corporate regulation is broken and small businesses and new ideas are able to flourish in its' absence.
As to your last point - having a single alternative is hardly a flourishing marketplace where the best ideas win. Distributors should not have the power to determine winners in the marketplace, and Apple's private power as a distributor of hardware and mobile apps has become such that they can ensure their own success regardless of whether they innovate or their customers love them.