You can't really compare a wild snake to the snakes we have in captivity. Snakes in the wild brumate during colder periods because they don't have a choice. There are probably a number that die during this time because of the effects of cold or due to not having the conditioning required. Brumating in captivity is really a choice for the individual keeper. I personally give my snakes 24/7 heat in racks until they are 18 months to 2 years. I also breed my snakes therefore, once they reach breeding age they are cooled for this reason. Another reason to cool your snakes would be to have a bit of time off during the year from cleaning and feeding. I haven't heard or read anything about ill health or longevity due to keeping them heated all their lives but there are also not many people doing this as long term keepers generally breed.