Outrageous, especially considering the price of competing products of similar (or higher) performance. They could come out with a regular price and a supporting price, making clear that you are not just buying a product in the second case, but making a contribution on top of your purchase. Or they could ask for donations straightaway.
A classic Uno has non-standard pin spacing too, but at least shields have become a sort of informal standard of their own, and they are plentiful. Or you can get a Nano with male pins and stick it into a breadboard. That "work of art" even has solder holes, like I'm going to sacrifice a board of that price into a permanent installation. But thinking about it, to do that I'd have to buy the board first, which I won't any time soon, so no problem for me.