Apple also pursues this strategy, but they don’t push it nearly as far as Samsung. The cheapest iPhone, the SE 3 at $430, has a 5 nm chip in it, which they only released two years ago. Apple just isn’t willing to release a parts-bin device, because they have a high quality bar. This is part of a moneymaking strategy, but my point is you can’t compare the A03 price to any current iPhone model.
Apple’s hardware margin is 35%, that is a reasonable estimate of the premium Apple is charging over a totally generic phone.
The are not totally a monopoly. They may be that in some peoples influence. But mine for example my parents literally would not be able to tell the difference between a generic sub 50 dollar phone and a 1500 one. They do not use any of the extra features and it would be meaningless to them. For some people it is about the status of that logo on the back. For others it is the tech stack and integration. For others it is just something to text and phone with.
It's Apples install base, app ecosystem, and social moat (iMessage) allows continued high gross margins on their hardware and locks competition away from their profit center. The sale price has very little to do with the marginal cost of production and a ton to do with a naturally occuring software monopoly.