Looking at videos, reviews and pictures Westone is about the same. The pro-range seems to be made of acrylic plastic which is better, but the consumer line doesn´t seem any superior to Earsonics to me. Shure on the other hand has very nice build quality, but I don´t think they are competitive with many others these days and really need a full redesign. Good build quality is extremely rare in high end IEMs. The only ones I can think of are Sennheiser IE800, Sony EX1000, FitEar, Audio-Technica CK10-100 and Heir Audio. It seems build quality is very expensive. Doubt the SM64 would hit its anywhere near its current price with an acrylic shell or even worse a magnesium or carbon fiber one... Sure the build quality on SM64 is nothing special, but it´s not really that bad either for a high end IEM. At least the bill of materials goes to what´s inside the cheap shell :) Looking at the pictures it looks like SM64 is really full of stuff inside. Compare with transparent Shure´s and you´ll see there is a lot less inside.
Ideally I´d prefer companies to sell two versions of their products: a plastic cheaper one with the same SQ and then a higher end magnesium/acrylic one so customers can choose if they want to pay for it. Fischer Audio does this by the way in their FA3/FA3-XB range. The standard version is aluminum with fixed cables, but the ergonomic design acrylic one with removable cables is around 100e more expensive.