Can someone explain to me why browsers allow the tracking in the first place?

Why isn't there a possibility to turn info gathering off completely?

Like, those instances need the browser to comply in sending the data in the first place, right? Can't the browser just send "you do not have permission to receive this info" each time they ask?

I get that websites need to know your browser version in order to show things properly. But all the other data they gather isn't really necessary, is it? Why would they need to know my computer version for example? And all the other things they use for fingerprinting.