Apple intentionally prices a lot of customers out of their market. Their monetary strategy relies on it, oddly enough. If they sold to more people, they’d run into many more issues being seen as a monopoly.
Tim Cook spelled it out pretty clearly to Congress when he testified last week; Apple does not have majority market share in any market they’re in. Not in smartphones, tablets, laptops, desktops, or wearables. And they don’t want to have more market share. The inflated prices and being seen as a “luxury brand” is a great way for them to continue making a huge profit while restricting market share to the point that they can skirt around most monopoly law.
The downside there is to maintain growth, they need to continually push into new markets, which they’ve been doing about once every 5 years (desktops -> laptops -> phones -> tablets -> wearables -> automotive/AR?)