Economies of scale, my friends... If I order (for example) a pair of Vermont Maple M50s, they have to get out the Vermont Maple vinyl which I'm sure they purchase in lower quantities than the Boston Cherry, therefore losing volume discount, and pay individual attention to my speakers.
BTW, it's the same stuff on the custom finish and normal finish; I've compared mine to Peter's Boston Cherry M22s and my Manswood Beech QS4s.
And if you think wood is going to cost just $90/pair, you're smoking something. Did you see how much work goes into those things? It probably costs Axiom more than $90 just to do the staining!
