Our games (i don't play single player most times) usually end, when most players start getting bored. In most cases this happens long before we explored the whole map, or even looted everything. Usually that kicks in when players have almost maxed their characters, can craft everything, and are superior to bloodmoons and the only task left is to craft enough ammunition to stay superior during the next bloodmoon.
I guess the longest play i ever did, was the second try on navezgane, where we also explored more or less the whole map. But most players coincidence was, once you know that prebuilt map, it is boring to play it again (even if it changed a little during update, but the basic layout is still the same, so you know right from the start where almost everything is located). Iirc in that playthrough we ended up on day ~180. And we did not loot everything, because why?
It only happend rarely, and that only if we played self-made "scenarios" like playing nomade (not using a location for a bloodmoon twice, which also makes it almost worthless to build own defense bases), that we stopped a playtrough because we got absolutely wrecked by a bloodmoon.
