I think it's more common than not. I'm in the same boat fyi. I think what happens after an interview is you fall into one of 3 buckets:
1. They like you enough to give you a seat. I think around half of interviewees get acceptances so this is the largest group.
2. They really can't stand you and reject you out of hand without even bothering to see what else is coming down the applicant pipeline. This is the smallest group and happens rarely.
3. You're decision pending, the second largest group. In my mind, that means in an ideal world they don't want you in their school, but the world is not ideal so they want to see whether there are enough "perfect" applicants still down the pipeline to fill their class before they officially reject you. If they get through the whole interview process without finding enough perfect candidates, they'll begrudgingly reach into the "decision pending" pool to fill up that petty-cash cup with your tuition and happily reject the rest with a "whew! only had to take in 15 decision-penders this year! Pop the Champagne brahs!"
But that's just my take on it. As the hodge twins might say, "Think whatever the Fuk! you wanna think."