Well, whether or not its getting more popular where you are, I've done my share of converting. I've converted my entire family into shooting 10mm, as well as most of my friends. I'm currently working on my fire station. I have probably helped sell about 20 10mm's just in my circle of friends and family.
Our wal-mart has winchester white box in 10mm on the shelf from time to time.
Every gun show I've ever been to in the last decade had at least a dozen 10mm's for sale.
It isn't losing any ground. Who knows if its growing or not. Its all I shoot. I've sold everything else off. And i'm going to have a 10mm upper made for my AR SBR.
Having 5k rounds helps though.