I wear a pair of Sorels that are 36 years old. I've replaced the liners and laces, of course, but the leather uppers and rubber bottoms are still working. I put a whole tin of Dubbin into those boots in the first coupla years, and the leather is still soft, supple and waterproof. I've worn these boots icefishing for decades, exclusively walking and sitting out on the ice all day.
I recently cut a foot bed liner out of closed cell foam, used for packing material. That will make them so warm I might have to take them off from time to time.
Pack boots are definitely the warmest for icefishing, and those Kamiks look deluxe. They don't do well treking over heavy terrain tho, and the hiking hunting style of the Rockies would be much better for that, with more support, tread, and a smaller outline.