I'd be interested to see your bookkeeping because I find that hard to believe. As a lord you get 50% of the tax gold from vacant estates. Occupied estates only give you the "lord's share", usually around 10-15%.
You say he is wrong, yet you claim that because lord's share is usually around 10-15%. Why is it usually that low? Because lords aren't as greedy you make them out to be.
Knights are only a harm to lords if they choose, because they can take up to 50% if they want of their knight's income, meaning the lord would lose nothing, yet the region/realm gains gold. So in other words, lords aren't really that greedy after all and there really is no downside to knights, despite you claiming so. A lord who wants max gold and power can give himself the largest estate he can and have a lord's share of 50%. Simple as that.
As an add-on, you didn't read his post that well, because he said the region produces more gold, not his lord gains more gold, because he loses no gold, yet the region really does make more gold. (Assuming 50% lord's share which he probably doesn't do because his city is so rich he has no need to.)
To all your benefits you listed of this, its false, because a number that holds no power is simply a number, and thus isn't promoting any of things you claimed because people don't care about numbers, they care about power. To the recognizing a character's rank, that is already done via their title. If they are a duke and you are lord, they are more powerful, simple as that.
