I don't think that any tyres are designed to last very long at all. The MOT stipulates 7 years max, and I've just replaced the set of four Hankooks that I put on my Rover 75 as soon as I bought it in July/August 2019. I suspect it's something to do with the fact that they are made of recyclable shit rather than the proper rubber and infinite-life hydrocarbons like they were in the good old days.