Did the police report say you were at fault in any way?
I don't know what these guys are talking about only getting 5k-15k miles on their tires. Some tires come with 70k mile warranties; companies wouldn't dream of giving a 70k mile warranty on a tire that's only expected to last 30k miles. To get that little life out of a tire, you are either seriously out of alignment or driving on a lot of rough roads too fast.