If you buy a computer from ASUS, you can download whatever browser you want. If you buy a cellphone from a Android-manufacturer, you can download whatever browser you want.

But if you buy an iPhone, you can only download browsers that are using Apples own browser.

Just because smartphones have traditionally been locked down, doesn't mean that it should be like that.

PCs were also pretty locked down the beginning. And Windows have tried a couple of times to move in that direction. But fortunately, we have a relatively open ecosystem when it comes to devices we use for "producing" things on. It's just missing that the devices we "consume" on works similarly.