I would say going to USC over Temple would not benefit you.
I would believe USC students do better than Temple students getting in. You said it and I’ll believe it.
If you look at Harvard Law, as an example, 174 schools are represented. So yes there are Harvard and Yale grads but also Temple, U of Kentucky, Ole Miss, etc.
Would there be similar amounts ?
No - because if you were accomplished enough to get into Yale to begin with, you’re likely also the cream of the crop headed into Law School. In other words, while most every Yale student can get into Temple the reverse is unlikely to be true.
So pivot to medical school - the concept holds true. There are kids at Arkansas or Arizona that can and will get into a top med school.
But there are fewer top kids there than at a Harvard or USC. It doesn’t mean their chance is any less assuming credentials are equal. It’s just there are fewer kids at that level at that school to begin with.