The DWS 06 has a 50k mile treadwear warranty. Let's pretend it doesn't go a mile over that, and that the others will last about that long.
$500 / 50,000 miles = 1 cent per mile
$715 / 50,000 miles = 1.43 cents per mile
Consumer Reports once estimated the total 5-year cost of ownership of a new Toyota Prius at 47 cents per mile. Just for kicks, let's assume your car costs half as much to own.
The difference between the best tire you can get and a tier-2 "it's good enough I guess" offering saves you 0.43 cents per mile. Out of 23.5 cents per mile, that's less than 2%.
Given that your actual operating budget is likely higher, the actual percentage saved will be lower.
Then you have to factor in the fact that the DWS 06 will be MUCH better near the end of its life than the other tires will be.
Come on, man! Do the right thing!