why do native English speakers constantly mess up your/you’re and their/there/they’re?

as non-native English speakers, a lot of my peers and i notice that native English speakers (irl and online) mess up their grammar more than non-natives. is it because they already know how to speak the language and dont bother to pay much attention to English language classes?

not a jab to anyone btw! just genuinely curious on the observation we made growing up :)