Gold sinks are problematic. Let's look at the suggested:
1. Lower monster loot: Doesn't work. Monster loot has gone up and down over the years, and the inflation is constant. Zombies had no gold. Zombies have too much gold. Zombies have no gold again, but a body part. Zombies have gold. The gold on them has gone up and down over the years, yet inflation has remained constant. Those who farm gold just pick a monster with the best gold per minute ratio. Changing the rate of gold coming in doesn't matter if the rate going out is practically zero.
2. Taxes: I don't mind paying taxes in real life. Civic responsibility and all that, and I know I have taken advantage of a lot of the "perks of civilization:" a police and emergency response force to keep me safer, public works, public education, education loans, national defense, etc. I DO mind paying them in game for nothing. The idea of a tax on stuff or houses in game always seem more like a punishment for success rather than some civic responsibility. Maybe a war tax system that had some roleplay application, but as suggested here and in the past, no.
3. Lower reagent: won't work. Take the example of potions and bandages. I could gather the material to make cloth, or I could buy it and just cut it into bandages. The gold for a lot of bandages is a trivial amount. Potions are still made from reagents, and people burn through a lot of them, but I still buy them from players rather than saving myself money and making them with a GM alchemist I already have. Because the cost is trivial compared to what I could make actually stocking my vendor with a few things I have sitting around the house. I actually use reagents on a combat mage because I wanted a 70s set with 45% DCI. The insurance cost for the armor is higher than the cost of a reagents in the bag.
4. Deleting gold: I hate this idea because I did put some work into gathering the gold and items I have. I did this because I believed this was a persistant world. If because of dupers and scripters and other cheaters, this illusion would be destroyed, I would probably move on to other things. I play to roleplay, and I hate the grind. I do the grind because it facilitates the roleplay and the exploring and the random events. If I was going to have to do another grind, I would have to consider options that were better for roleplay (other games, player shards, etc.). For those who like the grind and powergaming, they would hate this more. This idea would only kill UO which would certainly make the problems of gold sinks in UO disappear.
It also wouldn't fix the problem since scripters could run rampant again. Most inflation in UO is caused by scripters I suspect.