Nvidia is doing this since forever, but now the margins are even slimmer because of the build costs. The board has the size of a minivan that needs to be cooled. NVidia is like "i gave you the boards it's on you now", and this is why the extra 800$, because you also pay the Asus, Gigabyte, branding, where as if you buy a lower tire manufacturer but the same cards, might be a bit lower, not really MSRP, but closer.
Ultimately they can charge what they want. But no one is buying a 5080 for over 1200 max. Just like no one bought the 4080 at 1200