> The reason I think this is needed is because a large percent of Internet users cannot afford hosting personal websites. The privilege of self hosting that early Internet users enjoyed was never given to the new Internet users.
If you actually have the technical chops to self-host a personal website in your house, why on earth would you want to do it on a phone? A Pi, Nano, Jetson, NUC, any kind of small form-factor mini PC is a far cheaper and better option if the limiter is seriously that you can't afford a hosting service. A web server does not need a camera, a touchscreen, a gyroscope, a GPS chip, a radio transceiver, an accelerometer, a fingerprint reader, or any of the many other hardware features that cause a phone to cost so much.
You may as well ask why your thermostat, printer, microwave, smart lightbulb, or television can't run a web server. There is nothing technologically stopping them. If they can run a stored program and connect to a network, they can bind to a port and listen for incoming requests. But running a website on them just isn't the purpose for their existence. General purpose computing devices exist and are cheap. If you want one, get one. There is no reason every single device that can do any form of computing needs to be a fully general-purpose computing device.