It's probably the same reason the Fathom events got dropped. They might not feel the need to advertise this as much. The customer base is established, and the rest of the seasons are going to sell regardless.
I really don't understand this strategy. With the Fathom thing, it seemed like those were selling and it was bringing Star Trek fans together. As for the screencaps, it whetted the appitites of those people who would buy the set and maybe even get new people to purchase it. Not everyone is purchasing all the sets and it isn't hard to post pictures of what we can expect. To want higher sales figures (And they've said this because they wanted to see how TNG would sell before they did DS9) and then not promote it seems counterproductive.