The problem with LotR is that is isn't Warhammer. For 20 years, people collected fantasy miniatures for a different game, released by the same company.
From what I've seen, LotR didn't really have anything other than "skirmish" rules that WFB didn't already have... and Warhammer already has a much larger scope of races and player base.
I started my GW hobby with WFB Orcs and Goblins, before more or less leaving the Fantasy setting for 40k, because I enjoyed that game much more. If I wanted to play in a fantasy setting, my first choice would be to return to Warhammer, for a much better selection of models and a better ruleset, from what I recall and have heard.
In 20 years, I've seen GW start and abandon tons of "small scale" games. Inquisitor, Blood Bowl, Epic, Warmaster, That game with boats
, Space Hulk, Hero Quest, the rune-quest type game?
. LotR always felt like it would be one of those games, and I think they only reason it hasn't been abandoned is that there's probably some kind of contract for film support.
If I wanted to play a well supported fantasy game with the "best" following, I'd play Warhammer. If I wanted to play a good tabletop wargame, I'd play 40k, which I do. It also happens that in London, ON, there's probably a 8 to 1 ratio of 40k to WFB, according to the GW guys. They wouldn't even guess at the ratio to LotR players, but they have stories of "the last time I sold a box of those", whereas several Dark Vengeance boxes are sold each week.
My guess is that LotR tends to be fueled by fans of the series, that buy the models and those models happen to have a game attached that they can
play when they aren't adoring their favourite characters on a shelf.