I grew up in the NYC area.
So many 50,000 watt clear channel stations in that area, it made it difficult to listen to stations outside that area on regular AM radios.
As a teen, I built a Heathkit shortwave receiver and, with a long wire antenna, I was able to receive WLS after dark.
A few years later (still a teen) I acquired an RCA Radiola radio that was built in the 1930's. It was given to me by a friend of the family who was cleaning out his basement.
With that radio I was able to receive a Detroit AM radio station on 760 kHz during the day using only a 10-foot antenna along the floor of my living room. That is a notable accomplishment for that radio because of the local 50,000 watt station (WABC) on 770kHz.
The selectivity of that 1930's radio on AM has been unsurpassed.
Which leads me to wonder, was that intentional, or needed, back then? Or was it just Engineers designing for a world they could not envision?
fwiw, I still fire up that Radiola from time to time.
Nearly a century old, and it still works.
And works excellently.