RMT is for special people, buyers and sellers. Both are special. In that the sellers for US$ provide the means as a way to get some income, and the buyers short-circuit the very things that make the game exciting and hugely pleasurable for a majority of UO players. So easy-life bank sit and wombat bashing is cool, as is cool to pay 10 bucks to get your coveted item from the "Avatar" website or other. But then the buyer loses the intrigue, the challenge and intensity of "getting their own" either alone or with guildies/friends. This is the very sole of the game play. You paid 10 bucks but lost the game, really. No adrenaline rush, no danger, no challenge, no pain, no excitement, no dopamine rush.
The game provides everything you need without resorting to RMT with outside sellers for US$. It is a challenge. You need to be "special" to buy RMT goods from Avatar. Figure out why that is.
Everything is a challenge. Placing a castle, getting PS, getting legendaries, and upper tier content.
But the biggest fun in the game is owned by the little tamer with no uber gear, in ATL that goes around with a bright green dublet, crummy armor and no Hawkwind's, and tames 120 Cu's per hour, fills the cave with dogies, day after day, to finally hit a Red or White dog. He learned the trick of staying alive and tame dogs like the wind. One of these days he will get his beautiful bright paragon color cu, that will be his own accomplishment. He dreams about it sometimes. But he wants to catch it himself. And he can easily cheat and pay $200-300 from Avatar, but that would mean the end of fun. Other times he hunts Rikkie, and other spawns, gets killed by boss few times, and at times by the friendly PK "helping" with the spawn, one time he got stolen from, and killed the thief a few times, and goofed not to loot his corpse. That is exactly what is fun. The process of the fight or struggle.
Most of the real fun in the game is not owning stuff but actually getting there, and the process of getting there the actual fight, the frustration of searching for a plot to set a castle, even where there is none. And there are servers with available castle plots, for those who for some reason want one. Also you can buy one but with game gold, that you got from selling EM items, hard earned drops etc.
Also you don't need to have 120 PS pet to be extremely effective either.
Paying RMT Avatar and other websites makes us just "show" players, and really takes the fun out of the buyer and prevents the adventure part that makes the game fun.
At least this is my opinion.
(But other folks RMT frankly has not affected me or my game. Not that I can tangibly see, since my expectations in the game are just very simply to have fun, and that is all. No major trophies or golden castles, or hundreds of shiny pixels.)