Nope, @Nikkih, houses are not protection from culling unless the sims are also in "My Households" rather than "Other Households".
@Simmingal, you only get an actual notification of a sim who is culled if they 1. Live in a house and 2. Are known by one of your played sims. Which means there's surely plenty of sims who are eligible for culling where the only way you would know they were culled is if you somehow care enough about this unhoused, unplayed, unknown sim to notice their absence.
The limit on total sims in the game has also been raised several times and is now up to something like 800. The odds of you noticing a sim being culled out of 800 sims when it culls mostly unhoused, unknown sims in the first place is kind of low. That said, in my game, with all of the households I rotate between and how many total sims they know between them, I see culling messages a couple of times in each generation.
