But the reason you can afford to have that attitude ("If they don't like it, they can get the f out!") is that you can maintain the same level of income with or without them. My argument is that there should be meaningful consequences when knights vacate the region.
There is. The region makes less gold when its just the lord in command. That means the realm is hurting because its region's aren't making as much gold as they can. And if you look at cities, there are plenty with 5 or 6 nobles. Townslands will tend to have at least 1 or 2 knights. The rest previously I will admit it wasn't overly common to have more than 1 knight, and it wasn't exactly rare for it to be just a lord. The Ice Age and Monster Invasion are changing it from it being normal to have just the lord.
I will state this, realms with higher density though are almost always better, funner, stronger realms than those with low density. Realm size does take effect, but higher density certainly helps a realm. (Its also generally caused by the realm being fun so things to tend to be a cycle in growth/shrinkage)
