They don’t interview you after, if you match you’re “stuck” with each other at that point. I do think places are more likely to interview their top applicants for residency to get to know them better since it’s a longer commitment and you work more closely with that one group during those years, but you never know what a program will do. There is no requirement that they interview anyone. Even if they do interview some, they may still put people they didn’t interview on their rank list to try to make a match rather than have to scramble. It’s possible to match without interviewing. I didn’t get any interviews for my internship and I still matched. But even if you don’t match initially, the scramble is a perfectly valid way to get a position.