So people are paying SoE to help make the game for them, that they'll in turn pay for, in hopes of receiving royalty payments for their DoorIron_04 creation?
Theoretically. Realistically only .00000000000001% will actually try to make money and take that part really seriously. The rest are paying to mess around in a AAA Minecraft because they do not have the patience to wait until it is released to the public in open beta/release.
Not that I know the state of how or what you can make money on it, but it goes without saying that within the very first few months you will have hundreds, if not thousands of generic art assets. However, some will be upvoted, some will look better than others, and if this thing picks up, with millions of people playing it, and you happen to sit on the royalties of a generic asset, only earning you a few cents per transaction perhaps, that can still turn into big numbers.
Think of it like Skyrim mods. Lots of collection packs, but certain things are put in nearly all of them within the same category. So someone can make a default dungeon kit for 5 dollars with your 5 cent torch in it, you would get royalties for that. Say that remains the most popular kit (once something becames popular, it never fades from those lists. Same 5 star mods are still at the top of the search in Skyrim today as they were years ago), over time, that can give you noticable income depending on how popular it is. Hence, you are more likely to earn money from this Landmark gimmic making the small things that gets bundled up, rather than investing the time to create Lower Guk or something like that, which hundreds will, but few will do good. Getting in a few months after release, or worse still years, you will have little to zero luck getting any item you create upvoted because I am guessing their search engine will be similar to all others, "sort by rating". Few people add the search parameter "new", they'd rather use the tried and trusted "all time" and get the 4 year old 5 star rated collection.