Hence the second part of my post. If there aren't any construction differences, then simply being associated with Firestone is enough to warrant reducing the price by 50%, or it points to Kumho overpricing the tire when not sold as a private label.Not necessarily true.
A lot of Costco's "Kirkland Signature" items are nothing more the repackaged name brands. The exact same product. No cost cutting, except advertising.
At most the packaging is different (like a sidewall branding on a tire). To some people paying for a name brand (even though it is the exact same product) is important to them.
https://hip2save.com/tips/name-brands-behind-costco-kirkland-signature/
Which, honestly - Firestone being Firestone - I can understand, but $175 for a basic touring tire from Kumho is way beyond what I'd pay also given that's getting close to Michelin/Continental pricing.