There is some merit to that as in ‘new’ correctly stored tyres may not be much different from a young dated set, but an older set fit to a low mileage barely used bike is a totally different ball game. When I bought my B-King it had covered just 1800 miles from new, was always stored in the house and meticulously looked after. First few weeks on the bike I really really struggled with putting the power down, anything overly keen and a think black stripe would appear behind me. Cornering and lean angles were weak and I generally just didn’t have confidence in the bike. I put it down to being a big brute of a thing that must just handle like an Ox and the near on 200hp with zero rider aids was the reason for constant rolling burnt outs. However in a bizarre twist of fate I had another forum member contact me asking if I would sell him my original tyres that I still had fitted. He had a very low miles 100% factory bike but it didn’t have the factory tyres. He offered mental money to buy them off me so I fitted a set of Metzeler Sportec M5’s. Well the transformation was just indescribable, no more wheelspin , zero chicken strips left on a 200 section tyre with pillion , and a bike that actually went round corners. I cannot emphasise enough the changes a decent set of rubber make to a bike.
I did a track day year before last on a 20 year old pair of tyres and didn't die... wouldn't recommend it generally but actually once they were scrubbed back in they were fine.
