I can pull WSM 75% of the nights here in Winnipeg, WGN, and WLS, WJR among other clear channels. I listen because they often have unique shows (local talk, OTR on weekends, different regional sport events). They should be protected, with the caveat that they must not air syndicated programming. If you want night time protection show that you give a damn buy having programming unique to those hours. When you have multiple spots on the nighttime dial with coast to coast or red eye radio what's the point? network programming should go to smaller stations so less over lap at night. Maybe do another NARBA type overhaul if things get that messed up, so you have the local graveyard channels, and a chunk for AM micro-broadcasters, and then clear channels, and throw a couple of 500, 000 watt blasters (who could afford them though?) in for good measure (that'll cut through the wall wart noise!) Perhaps those few blasters could be set up as terrestrial music streams much like on satellite radio but live hosted. That way you'd be guaranteed a large enough audience (remember it's free on any old AM radio over a wide geographic area to compensate for a niche format).
In the end the AM dial needs a little more variety esp. at night. Wouldn't it be great to hear different music or spoken word programming on AM? Stations are becoming advertising beacons and programming is getting too cheaply produced with shock jocks shouting indignant about some guaranteed hot button issue to rile people and get ratings. Syndication is only good if you're the only station in a given area broadcasting it, and automation works only if your playlist is unique. When it comes to music programming it's hardy a Laissez-faire situation with all the "market" research and centralized consultants results in similar playlists in a given sure-fire format. Either buck the trend and invest some cash to add value and make it a good station to listen to. or let it go and let NPR or Public access stations crop up in place. Religious stations may well fill the band like on shortwave. Reminds me of urban decay.
I am in receiving distance of a couple interesting local AM stations, one is CBC (NPR-ish programs) documentaries, comedy, science magazine programs, by day and BBC, Deutsche Welle etc. segments by night. Another is a full service rural country music station that switches format to classical music at night.
Shortwave broadcasting is not like it was in the 1990s, but I can still DX many interesting stations that are very different than the MW and FM stations.