The nature of a free market is that someone wins the competition, and the winner is then happy to figure out ways to prevent anyone from competing at all (this kind of action doesn't require a complete winner either, but I'm focusing on a thought experiment here).
Ergo, if you care about maintaining a free market, then you care about limiting what kind of moves you can make in the free market, in order to preserve a free market. A truly free market with no rules has an end state where it is not a free market, more like a much more sophisticated version of the nobles of the land owning everything. So we declare many activities that make it difficult for others to compete that are not simply about manking a better product, "anti-competitive" and illegal.
Other than capital what prevents a new player entering the smartphone market? In the US Apple is at ~50% market share and Samsung ~30%. These are not colluding entities so there must be enough theoretical freedom to create a smartphone that claims significant market share.
Other than capital does a lot of work in that argument. Companies will not pop up and optimize much less micro optimize the tradeoffs. This isn’t a stock exchange; it’s a real capital intensive product.
Microsoft, Amazon and Meta have plenty of “capital” and they couldn’t create their own ecosystem for their own phone and convince software developers. The hardware is not really an issue. Any company with a few million can sell their own phone and get a Chinese ODM to customize it for them and white label it.
Outside of Apple and Samsung (only because they make a lot of their own parts), the phone market is a commodity race to the bottom
Amazon, Meta and Microsoft tried their hand at making competitive devices and enter the market, to varying degrees of effort but practically identical degrees of failure. All this to say, it takes a lot more than just capital.
Arbitrary software limitations such as apps not running on said phone.
The apple iPhone is a locked down system engineered in such a way to extract maximum value from consumers and developers. It is impossible to compete.