Turbine has decided to forgo developing new raids for Lord of the Rings Online (at least for the time being), it all comes down to numbers. According to CM Rick Heaton, raiders make up the smallest portion of the playerbase even if they are quite vocal on the forums:
Raiders comprise the smallest, by far, group in our game. PvMP players are far larger and even they are small. in fact together the two groups wouldn't comprise 10% of the total player base and never have (this is important. it's not a new thing, it's a long standing historical fact).[Thanks to Dan for the tip!]
Forum posters comprise a slightly larger group than the combined group of PvMP and Raiders. However, Raiders and PvMP players make up the overwhelming majority of forum posters (More than half. Though raiders are the smaller group of the two (PvMP/Raiders)). So you have a tiny group, inside a small group that is grossly disproportionately represented on the forums.