Nothing stops anyone today from running Narrowband in GMRS. If the repeater owner thinks that setting the receive window to 12.5 Kc will improve the receiver performance for their particular situation, they can do it. Most repeater owners run 25 Kc wideband because it works better and sounds better. The day that 12.5 becomes the better alternative is the day most will switch. In most parts of the country there is ZERO issue with channel congestion in GMRS. I'll keep mentioning this until folks get it. If you want to run DMR, there's nothing stopping you except for a Part 90 license. Go get yourself coordinated for a Private Carrier license for DMR, and invite all your friends and family to join in. You'll be talking Digital in no time.