Yeah, it sounds like a pretty standard tire warranty.
Look at it this way: You have not lost the "full value" of the tire because the full value of the tire is the use of the tire for its entire useful life. If your tire has a 50,000 mile warranty, then it's expected to last you 50,000 miles.
Now, you've gotten 39,000 miles worth of use out of it, which means you've received 78% of the value of that tire. What you've lost is 22% of the value.
$190 x .22 = $41.80, which is the value of what you've lost. Seems fair to me.
Having said that, times are tough for everybody including people who sell tires. See if they'll cut you a deal on a new set. My guess is they will, just to keep your business.
If they won't deal or cut you a break, shop around a bit. It might be galling to not get compensated for a broken belt, but if you can save more than $41.80 on a set of tires someplace else you come out ahead.
The most I've ever paid for a tire was around $140, taxes included and that was for a set of Yokohama Geolander AT/S tires in 235/85/16 that I put on my Tacoma in 2007. This was at Discount Tire.
