You said:
"Funny .. even the ARRL has removed the de facto 21.430 MHz AM Calling frequency"I don't remember the ARRL ever Id'ing an AM "Calling Frequency" for 15 meters. I still have a chart I printed from back around 2008 or 2009. Nothing on there, Just like there's no "AM Calling Frequency" for 10 meters either. There's a range: 29.0 to 29.2 MHz.
Now during the last cycle, when there was abundant AM activity on 15 meters, "we", in a number of forum discussions, sort of identified a range from roughly 21.415 to 21.440 MHz where AM could be found.
However, even on the AMWindow web site: AM Frequencies 15 Meters: 21.285, 21.425
Note that on 20 meters, the "AM Calling Frequency" identified by the ARRL for years is 14.286 MHz which is 1 KHz away from the QRP Calling Frequency and a bunch of other activity that always seems to be around that frequency. This is why, years ago, most of us moved up to around 14.330 MHz for AM activities. However, this is now the same area where you'll find a lot of "X"OTA activities too.
Life can be rough. Grab that big knob and tune that radio; AM isn't that difficult to find