You can uninstall apps (application, aka programs), but you cannot uninstall the operating system. It is the operating systems that have added tracking capabilities. Following your PC example, you can uninstall a program like Adobe Acrobat, but you cannot uninstall Microsoft Windows.Forgive me for asking (never had a smartphone) but a smartphone is just a hanheld PC with phone capabilities built-in. So why can't you smartphone users just uninstall unwanted applications like you would on a PC?
(Okay, you can uninstall Windows, but for the PC to work, you would have to replace it with another operating system such as Linux and this is not currently an option on the phones.)