That's just for the rich, something the size of a fingernail just to store data for the price of the switch.
Even if you are wealthy I don't recommend investing too much, specially because they either already made or are making a god damn 128TB SD (the bigger one), I'm sure they will keep increasing little by little and win a HUGE amount of money while they actually can make something already hundreds of times better and they also come with PCI-E controller built-in and capable of around 1GB\s, its more like a full SSD in a small SD.
the 200 and 400 gb cards have recently been reduced in price so they are kinda affordable now. but a 200 is still much cheaper per gb than the 400's.
really, people make a big deal about read or write speeds, but at least when they're inside the console, the internal sd reader is easily the bottleneck of the operation.
and be real, the 2 minutes you save while putting files from pc to sd is nothing.
as for the rest, i'm not sure you should expect sd sized sdds anytime soon. and not at an affordable price either