This does not hold for any but a very-few expensive markets, and even there, not most of the time. Hell, I stayed in Manhattan a few months back with my kids, and for two beds in a room just a couple blocks from Times Square, in a hotel that I'd classify as one full step up from "just clean sheets and a door", we didn't pay $300/night, even with those being a Friday and Saturday night. And that was the most expensive hotel I've ever paid for in my life.

You went somewhere very unusual and probably managed to hit on a peak weekend for whatever reason.