I guess from your posting that most US stations transmit from just one FM transmitter. This is like some of the small "community" stations we have in the UK. Some of these are seasonal, and only broadcast during the summer.

The national stations and the bigger regional ones cover a bigger area with a network of transmitters with overlapping ranges, and normally use the RDS AF (alternative frequencies) feature to inform the tuner where to look when it travels out of range. This gives near-seamless coverage of a much larger area than a single-transmitter station (which would need much more power, swamping nearby receivers).

Of course, in a country like the US, particularly in the west, there are big empty areas where it's not economically worthwhile to add transmitters, whereas pretty much all of the UK is fairly densely populated, so the environment is quite different.

And so endeth the lesson of why RDS is much less used in the US than Europe (apart from "Not Invented Here" effect, of course).