Receivers, possibly. Stations, no. There is nothing to be gained by Congress by mandating a digital conversion. I suspect they're going to discuss pattern and power changes along with tower and frequency relocations so that local stations can maintain city-grade signals over their cities of license, regardless of the skywave interference it could cause, elsewhere. If they get the receiver mandate, then we might see some upper-band AMs go full digital. Might see that anyway if there's any money to be made. There are a lot of AMs that don't make a dime, NOW. Find a city where iHeart or Cumulus has a cluster with one non-performing AM and they might try something. You'd need to put a niche format on it that would grab enough affluent listeners to attract advertisers. If I were running such a cluster, I'd probably try an ethnic music/news/sports format based on the market's population. Even then, I'd still go with hybrid mode just to reach the largest number possible.
I guess I'm saying I don't see ANY reason for any AM station to use full-digital mode.
Walking the fine line between jaw-dropping and a plain ol' yawn.