Isn't that what Night Mode in AVRs is for?
And you can buy a power amp and speakers and stick them in a flat without any requirements for max levels or mute buttons, why would subs be any different? It's up to people to purchase what's appropriate and use it appropriately. You might be in a flat with very accommodating neighbours, or only play content during the day.
Not at all, night-mode is volume leveling compression, it is not sub=off. It allows you to still hear quieter sounds when the volume is low. That's its function.
Sub frequencies resonate wall materials and their cavities, and thus propagate easily through walls. Other frequencies are reflected and absorbed or strongly attenuated by passage thorough a wall. The higher the frequency the less you hear through a wall, the lower the frequency to more of it you hear through a wall.
Sub frequencies also propagate much further in the open air than highs do. High are absorbed very quickly by air molecules. But they don't absorb lows, those tend to drop away closer to the inverse squares law with radial distance.
When you hear the low volume level of the audio system of your neighbor across the street, at 1 AM, you only hear the lows, you do not hear any other frequencies at all. If their sub has a mute enabled you would literally hear nothing.
I don't live by myself on a farm, like 90% of modern humanity, I live in a city or a large town, and if I use my audio system without the sub-muted, at 1 AM, I am going to have a lot of rather unhappy neighbors. Why pretend this is not so?
