EA has a history of strangling the life out of MMO's. When micro-transactions started to be a thing, EA added micro-transactions as a monitization model but did not understand (or maybe didn't care) that to make that worth while you have to build a much larger player base by eliminating subscription fees, retail fees, or both.
World of Warcraft is the only successful MMO on the US market that I am aware of that has all three. Part of their success is their critical mass, or the "Facebook Effect". A lot of people join WoW and continue to play WoW because their friends do, which becomes a self-perpetuating cycle. At a certain critical mass this becomes self-sufficient. These can be referred to as Social Players, and will typically move to the game their peer group is also playing at the time and is open to experimentation with other games.
There are also Vacation Players. These players are transient, but come in huge numbers. They sub for a month or two after new content is released, then drop. This is typically when Blizzard and others report on their populations: just after content releases when the transients come in and the population hits a high water mark. EA hasn't reported on UO's population since, what, 2002? 2003? This is because that was the last high-water mark.
Finally there are the Die-Hard players. These folks play no matter what. They are hard to acquire, hard to loose, and few and far between.
Of the three player types, the retail box monetization model capitalizes very well on Social and Vacation players. This is why you see titles like Guild Wars 2 and DnD Online release with a retail price even without a subscription model.
Subscription fees capitalize well for Social players, but no one else. Vacationers don't stick around long enough and there are too few Die-Hards .
Micro-Transactions capitalize well mainly for Social players. Vacationers do not typically invest a lot in each game and again there are just too few Die-Hard players to buy your junk. This is why you see games with high numbers of social players, such as WoW and Runescape, being very successful with their micro-transaction model, whereas games that are heavy on vacationers like DnD Online are not.
All of this is to say: Ultima Online is a game of Die-Hard fans. You just can't monetize well off Die-Hards. In order to attract the other player bases you have to really invest in your product. It takes a modern client, game mechanics that are not tedious (reagents / ammo), and advertising. EA has not addressed any of these things. Their repeated attempts at newer clients have all been half-hearted (or maybe under-funded) at best. Even the EC client looks ten years old. Hint: it is! It's based on the KR client from 2007.
Never fear though! The free shard community is here to invest in the product where EA won't, and to support the Die-Hard fans where they are undeserved on the official servers.
