Why don't the manufacturers recommend LT tires??

Repeat business and profit. Ever wonder why you don't see double edge safety razors and blades in the stores anymore? Back in the 70's Gillette ditched the double edge safety razor in favor of the multi bladed disposable razor. It's always been marketed as being superior to safety razors.

In reality it's just overpriced razors with an excessive amount of blades that doesn't really last all that long. If you've tried to save a multi day beard with a week old cartridge razor then you quickly find out how "superior" they actually are. Running your face into a wall is more pleasurable.

Before I switched I used to have to pop in a new cartridge every couple of weeks because they degraded so quickly. That's how they keep you coming back for more. Over the last 5 years between my wife and I have yet to get through a $10 pack of safety razor blades. Over that same time period I would've paid well over $400 for cartridge razors just for myself alone. The whole ST vs LT thing isn't all that different. Just different companies and a different industry.