You need a basic understanding of those three physical ideas before we figure out why horsepower and torque cross at 5,252 rpm. It all boils down to the math behind both horsepower and torque.

Horsepower is torque times rpm over a constant. It’s literally torque applied over time. You can’t have high hp at low rpm with low torque, it doesn’t work.

Jason Fenske at Engineering Explained details why hp and torque always seem to cross at 5252 rpm in his latest video, but just be warned, there's lots of math involved.

He also posted what appears to be a graph from an engine dyno, which shows figures of 700 horsepower and 600 pound-feet of torque.