The same can be said for old consoles, or old non-smartphones that were also computers, had browsers, even in some cases have CPUs more powerful than contemporary iPhones, but didn't have any way to install apps at all.

There's no law requiring vendors to provide features to install apps on devices with CPUs at all.

You probably own a dozen devices containing CPUs, running software, for which there is no practical way for you to install anything. Apple provides a certain set of features in their devices, if you don't think that's a good deal, there are other vendors you can go to.