I think I said that...somewhere.   As the inventor of the SSD, back in August 1980, the only real option available was 64kbit DRAMs, eventually shifting to 256kbit (1983) and 1 mbit by about 1987.    S100 Computers - SemiDisk History

The unlimited lifetime, both read and write, of a DRAM was assumed...

However, I don't know enough about the disk-usage characteristics of this new kind of storage-crypto to know what the cost trade-offs are.  Can most of the 'disk' reads/writes be cached?  That would certainly minimize SD card usage, and thus limit the wearout mechanisms.    

                      Jim Bell