Hi NQC,
Yes, I've heard the argument before about operating in the MW band so the general public can tune in. I simply don't buy it. Radio listenership by the general public is at all time lows. Many simply don't listen to the radio anymore. Those that do listen to FM mostly (hence all the closures of AM stations). The few that do listen to AM are not tuning around the band, to see what's on those weird frequencies above 1600 kHz, where there's never a station to listen to. It's just not happening.
Even within the radio hobby, there's very few checking for MW pirates. This is probably (mostly) a case of "no one is listening for MW pirates because there's rarely any on... there's rarely any MW pirates on because no one is listening to them... no one is listening for MW pirates because there's rarely any on..."
If pirates want to operate on MW, and and be heard, they need to be above 1710 kHz, period. Every so often I hear someone on 1620 kHz, and invariably they're getting buried under Cuba, or someone else. Occasionally they'll be heard mixing with Cuba, and rarely with Cuba in the background. And of course 1710 kHz is jammed (I'm purposely using that word) by the Hudson County TIS Of Doom, with their now 5 year old recordings of where to go to get shots, with maybe an update about a road closure.
Not to mention the fact that the Pirate Act's multi million dollar fines don't apply outside the MW band.
I record 1600-1770 kHz 24/7, and use Carrier Sleuth to help me quickly go through the file and identify any possible pirate transmissions so I can then listen to them, either domestic or foreign DX (which I occasionally hear in winter). I even originally wrote it just for finding MW pirates! Shameless plug for those who want to download Carrier Sleuth and give it a try, also handy with finding "regular" MW stations:
https://www.blackcatsystems.com/software/medium_wave_carrier_display_app.htmlBut absolutely, advanced notification of transmissions is going to significantly increase potential listenership.
As far as why there's so little MW pirate activity (radio hobbyist oriented, vs those who think they're reaching the general public), I agree that part of it is technical. Antennas are larger and more complicated. Most modern transmitters can go down that far, and even older ones probably don't need a lot of modification since it's not that far from 160 meters - and if you operate above 1710 kHz, you're that much closer to 160 meters - another advantage!

Likewise for listeners, you need larger antennas to have a chance to hear low power (relative to MW broadcast stations) pirates. Being able to tune in the frequencies isn't an issue for hobbyists of course. There's still other issues, static levels especially in summer. Propagation - you need night time paths for any chance of DX. And the best time for reception of MW DX is local mornings, not evenings.
IMHO MW pirate radio activity is a small niche segment of an already small niche - radio hobbyists. I do think if there was more regular activity, that would lead to more listeners, leading to more activity. It's just getting to that point.
I think that's what happened to a large extent with 43 meter SW pirate radio activity, over the past decade or three it's gone from "I hope I hear a few pirates this week" to "Wow, there's ten pirate transmissions every day and there's three or four (or more!) stations on at the same time, I almost have too much to listen to!". If someone asked me "when was the golden age of shortwave pirate radio" I'd tell them "right now".
I should amend my last thought to 43 meter SW pirate radio activity in the *eastern* USA. It's still relatively sparse/rare out west. And I think it's the same reason - less activity means fewer listeners means less activity...
p.s. Maybe we should move this thread to the general discussions so others can chime in? Not many will see it here since there's so few MW pirate stations/listeners