I have an REI wheeled carry-on with a detachable backpack that i have lightly used for about 6 years. (three-four short airline trips a year)
My last trip I was wheeling through the airport and it started scraping like i had a flat tire, and that's exactly what happened. The wheel stayed intact on the bag, but the tread and separated and come off.
The bag is still fine, could get or purchase a pair of replacement wheels? It appears that you no longer carry this bag, but it really only needs the wheels.
You probably want to contact REI directly (perhaps in the Ask an REI Employee forum) with the model name or item number of your wheeled carry-on. They may be able to supply replacement wheels.
In any case, there are several videos on YouTube that describe how to replace wheels. You can buy replacement wheels on websites like Amazon and eBay.
If all else fails, stores that specialize in repairing luggage may be able to replace the wheels for you.