Even in a castle most of the loot you find robbing people stealthily is worth less then 5g per 1 pound. The only items that actually make the weight requirements of my lift rule are often rare and far between unless you count produce.
I can understand a peasant in the waterfront district owning nothing of value to take but when robbing the richest guy in the land I expect a guard and I expect things of value to steal. I expect gold plates that shout "I'm better then you" to the peasants who are never actually allowed to see them.
Without expensive loot in homes even if you aren't a thief the richest nobles just feel like peasants in big houses. It's like they were so afraid we'd beat the enemy levels with us to be equal power curve that went overboard replacing the glass weapons and armors in home with items that aren't even worth their weight in gold. There was a rare expensive dish (really rare) and a rare expensive bottle of wine but it was too rare. The thieves guild mission requirements reminded you this. None of it was flaunted publicly to show the peasants who the lord was and who the peasant was.
Skyrim is mostly poor or pragmatic people so I don't expect it to be the norm but when I'm in the house of a lord in skyrim I expect to find lots of stuff to steal or look at and know the high pricetag of.