Simple test: Swap the front tires - side to side.
1) If the pull completely changes direction, the pull is all in the tires.
2) If the pull doesn't chnage at all, it's all in the vehicle (might be alignment, might be a dragging brake!)
3) If the pull disappears or changes (other than a complete change in direction), then it's both tires and vehicle.
Be careful as many alignment shops won't fix a vehicle that is out of alignment if the factory didn't provide adjustability. That is utter hogwash. ALL aligbnment settings can be adjusted, but sometimes it requires an eccentric bolt or a plate to get the adjustability.
Also, if the problem is tires, you won't be able to get an adjustment from the tire manufacturer. They don't warrant tires with that much wear for pulls - only when they are new.