The astronaut image is 60"L x 90"W x 5.5"H. Solid wood. (Shipped in parts.) Yeah, guessing that's not going up on just a single nail into the drywall - at least, not for very long!
(I'd guess a french cleat anchored to studs.)
And yeah, they are expensive, no doubt, but it's a cool concept and appears well implemented for what it is. Functional art. Plus, "Each Piece Is Cut, Sanded, + Attached Individually" from "Local, Sustainable Materials". Eyeballing it, those look like 1" square pieces. So... 5400 individual pieces - that has to take a few hours!