The way it was explained to me years ago was that the AM receptor is twice more massive that it will defeat the purpose of the mp3 player being so small u could fit it into your jeans pocket.
I still have my 4 GB Sandisk player I bought in 06’ and use it on occasions because I get lazy changing songs on the weekends once I tire of the songs on my Ipod.
Yes. You need a decent sized ferrite core antenna for AM reception
There are also portable HD radios for $40-50 at Best Buy (Insignia)—they get FM only BUT some AM signals are
relayed on subchannels. For example, WEEI sportsradio
is on the HD3 of WMKK 93.7 and WBZ news radio is on the HD3
of WBZ-FM 98.5...here you have FM radio with HD signals
and “extra stations” on certain frequencies, and among those
are AM signals. No mp3, just a radio.