I think the Apps and games for iOS, and Android are still not as good as PC running Windows, Mac, and Linux, so there would most likely still be people who prefer using a tiny laptop or desktop PC.
Some types of programs like Photo and video editors work best with a keyboard, mouse, and other input device.
It is also more difficult to control your privacy and security when you use a mobile operating system because you may need to share your private information with Google, and Apple when you use their mobile OS. But, with PC, you can use operating systems like Linux where you have more control on what data leaves your computer, and is shared with the OS maker, and programs.
It is also easier to type on a small physical keyboard on a laptop instead of a small touchscreen keyboard on a smartphone or tablet.
