It sounds to me like changing tires are not an  answer to your getting stuck . . . . If it's that wet, tillage and planting will not give best results, as you well know. You didn't mention duals ? That would help as much as anything, but simple getting new rubber a couple inches wider when flexing isn't a solve all for ground that is too wet to be on . . .  Those are my thoughts based on your infor . . .