I actually think those kinds of mistakes are made more often by native speakers, because they learn it from other people as they’re growing up (including all the mistakes), while non-native speakers learn it correctly (from books and teachers). Same goes for the then/than or they’re/their/there, etc. When you learn it spoken first, and incorrectly, it’s harder to correct those mistakes than to learn it correctly from the start.

In Dutch, for example, we have loads of people who will say “groter als” (bigger than), which is dead wrong - it should be “groter dan.” This als/dan-mistake is something typical of natives, and I’ve never heard a non-native make this mistake. Same goes for zij/hun. Usually kids just learn incorrectly from their parents. My own parents make those mistakes as well and it took more than a year of my elementary school teacher correcting me every. single. time I made the mistakes, for me to correct them.