I am asking for the date codes on the sidewalls of the tires. That way, you can confirm exactly how old the tires are.
Also, I finally found a listing for the tire on Walmart.com. It looks like that tire was made in 4 different speed ratings, with varying mileage warranties.
"The Mastercraft LSR Grand Touring is a touring all season tire manufactured for passenger and crossover vehicles. Mastercraft offers a 50,000 mile treadwear warranty with the W speed rated sizes, a 70,000 mile warranty for the H and V speed rated sizes and an 80,000 mile tread warranty with the T speed rated sizes."
Maybe you have the W rated tire - which wears faster.
A couple of other comments:
1. I would worry about the brakes before worrying about excess treadwear, especially since you said it is even wear.
2. I agree with
@scar_cle - I would just get Michelins and be done with it.

3. Treadwear is not linear over the life of the tire. For example, if you have 50K mile tires you don't have 1/2 of the usable tread gone after 25K miles. The tread wear rate is initially higher (more flexing, etc) and then it slows down.