That has been a pet peeve of mine with Garmin for years. In NY, most areas have switched road signs to the "official" 911 names for roads. My Garmin still used the older street names. While I'm familiar with the roads, if someone from out of the area hears Maple Avenue from the Garmin, but the sign says County Route 7, it is a bit confusing.
When I was working with the Red Cross Disaster Service, this was a real problem when trying to find an address at 4:00AM in parts of the county I was not familiar with. Since they update maps at least 4 times a year, seems like they could update to the current names. I've talked with them a couple of times about this & they don't seem to be interested in a solution.