1) feasts were ways to use up overharvest that could not be properly stored for the winters
Bullshit (if you believe no king of old ever had a feast out of decadence, you are a fool) and even if true it would be besides the point. The point was about plentifulness. In addition one could make a point of the quality of the food, which for a king would be very good, even by today's standards. Haute cuisine cooking is not high-tech stuff. The ingredients are still key.
2) before central heating and insulation, the castles were drafty buildings that needed fireplaces in every inhabited room during much of the year
The servants deal with the wood and the fireplaces. Problem solved.
3) handmade furniture was the only kind at the time, mass production was an odd dream of a few
Yep, and you can bet your bottom that the king had the nicest handmade furniture in the realm.
4) armies were expenses, not luxuries
Yeah, tell that to the peasants who were executed without a fair trial. Even now, in the US, poor people are easily fucked over by the law.
5) the farmland is delegated to the Midwest states, and the produce available everywhere
Which poor people can't afford. They are mostly stuck with cheap and terrible fast'food'.
Also, the point was about owning land and having control over it.
6) who needs 10 horses when even a cheap car can match 50?
People who like to go horseback riding, play polo, hunt on horseback, tame horses, have horse races, or like dressage (you'll notice a trend of amusement and required amount of wealth here).
7) if you want the idealized pleasure of a hunt, Sony can help. If you want meat, check the market
Missed the point again. This again revolves around owning resources.
8) the old ships weren't as fancy as you imagine
Yeah, you could probably buy one of those for 10 bucks nowadays. Who the hell wants a sailing ship anyway?
9) ok, yeah the jewelry is hard to match as gold and silver reserves haven't grown that much. But the quality is better if you do get some modern bling
Your arguments get progressively weaker. This one is just laughable. In essence you are saying "modern poor people live more comfortable than the kings of old because even though the kings had massive amounts expensive jewelry, modern jewelry is slightly nicer if a poor person would have the funds to buy them."