A gallon of flash cards is great, but you do have to figure out which one you want after they are delivered. I'm wondering whether there is such a thing as an automated flash card library. I know people have archives of tapes like that.
The thing about flash is that it's cheap and easy to keep it all permanently online. You can get a stack of 2.5 inch SSDs for the same price as microsd cards, and plugging them into a bus takes less space than a tape robot.
When you're looking at the same price for two systems, and one is 100x-1000x faster at the cost of being 'merely' hundreds of TB per gallon instead of a few PB per gallon, nobody is going to bother engineering the latter just to save a few bucks on shipping.
