During WW II, rubber was scarce and we had gas rationing to preserve tires. People drove on anything that would hold air. Of course, the national speed limit was 35 mph. Part of whether or not to buy a used tire depends on the conditions under which it to be used. For example, I had a blowout on my 2003 4Runner. I did put on the spare, but wanted a replacement spare tire. The owner’s manual and the independent tire dealer where I trade both specified that the tires were all to be the same. The 4Runner had Dunlop tires and my tire dealer did not handle Dunlops. He said he would call around and get a price. He called back an hour later and said a customer had come in to replace his tires. He had the same Dunlop tires that I had and had about 1/2 the tread life remaining. He sold me a tire for a spare for $35. That beat paying $150 for a new tire. My late father-in-law always ran on Michelin tires. When he bought a new car, he would have the car less than a year and he would have all the tires replaced with Michelin. While Michelin is a great tire, someone got an excellent buy on the tires he removed that had gone about 10,000 miles.
Some years back, I had a 1950 Chevrolet 1 ton pickup truck. It had 7.00 x 17" tires. These tires were hard to get. I would buy any tire that had enough tread life to get through inspection. However, I only used the truck to do hauling for limited distances.
I think in making a used tire purchase there are two things: 1) what type of driving is going to be done on these tires; 2) what is the condition of the used tires.