We chose flash memory. It's a storage medium that involves a lot of tiny wires laid out in patterns going to the storage cell. We want to access these with only

We chose flash memory. It's a storage medium that involves a lot of tiny wires laid out in patterns going to the storage cell. We want to access these with only a few macroscopic wires connecting to a computer. This process has to be managed by a microprocessor of some sort. Would you expect the host device to know the internal layout properties and hardware limitations of a purely passive bank of flash memory (e.g. when to mark a sector as failed)? It's possible but distributing the hardware and software to do this effectively would be a very difficult problem, and industry standardisation to mitigate it would be hard to arrive at as well, and deploying advances in flash memory would be hampered (remember when people worried about 720kb/1.44mb floppies? Imagine that for each new generation of flash memory. Is your flash drive slot MLC NAND flash capable? NOR flash? TLC? HKMG?) Instead we live in a world where not just thumb drives, but even memory sticks and SD cards, are active devices. (This is, of course, to say nothing of the convenience of using one port for everything.)