The plastics are getting a little too pricey. I bought the plastic Dwarfs set a few years ago (when it was still $25). The set had 16 figures in it (not even a full unit! I play WAB too, and I rarely have infantry units less than 24 figures...usually closer to 28 or 32), so cost-per-figure was $1.56. Now, at $30 its $1.88. I invested in Harlequin/Black Tree dwarfs -- in metal, with good sculpting -- for the same price as the plastic set.
GW's metals, OTOH, are not THAT bad. For rank & file, the price is competative with other companies like Reaper. The perception of overpriced minis comes from the special units and characters (which ARE expensive on a per-figure basis), but for general units -- not that expensive.
If you find GW's price system odious, there's always historicals. Already play WHFB? Switch to Warhammer Ancient Battles, and spend less than half the cost for historical figures. I'd reccommend WAB for fantasy games just on principle (there ARE some differences, and I think they make for a better game).
As far as competition? There's always niche games. The problems with those, however, are that they have a much more limited appeal. Everyone can identify with orcs, dwarves, elves, etc. Iron Kingdoms? Definitely not my cup of tea, and I think the minis are ugly. Or how about Chronopia? Again, too specific and unique. Confrontation? Minis are expensive and over-the-top. Reaper's Warlord? Why would I want to play a skirmish game when I already play D&D? And so on...
Those are just my opinions, but I think the reason for GW's success is the fact their games are generic enough to have a wide appeal. I could easily use many of the figures in a D&D campaign without batting an eye. Not so with some of the above games...
Damon.