For a non-Haas bashing post, it is beginning to look kinda like one! But, that's okay.
As far as parts are concerned, it is because they have an extensive system of Haas service centers, dozens. The centers have to buy and maintain a large assortment of parts in order to be able to service the machines. It would not be proper for Haas to undercut these dealers and sell parts directly to the customers.
OMAX has a total of 14 distributors in the states and most probably don't stock parts, so online ordering is not a problem for them.
As far as getting the correct part, if you give them the part number, it is always going to be he correct one isn't it? I have found that most of the time the parts guys are pretty damn good. If you do have a problem, deal with someone else.
Mike
Two Haas VF-2's, Haas HA5C, Haas HRT-9, Hardinge CHNC 1, Bother HS-300 Wire EDM, BobCAD V23, BobCAD V28