The whole obsolete hardware craze is really a little overrated, as when it happened in the past, it was always with pretty damn obscure hardware. Of course not everybody has a machine around to read some old NASA tapes, so you will have trouble reading those in a few decades, but pretty damn near everybody has something around to read USB.
Ok, well let's think back to 25 years ago. 25 years ago was 1987, what storage medium was around back then that we could read easily now? 3.5" floppies were around, the 1.44mb high density format was brand new for 1987, how easy is it to read a 3.5" floppy disk these days? No computer comes with a floppy drive, you'd probably be able to find a USB floppy drive so it IS possible to read the disk (if the disk is still good). So it is perfectly understandable to be concerned if media from 2012 will be usable in 2037, despite your believe that the obsolete hardware craze is 'overrated.'
Personally, I'd store whatever on raw media like an SD card, since readers may exist in the future for SD->whatever-new-interfacethereis. A hard drive in 1987 may have had an MFM interface to it, see many MFM->SATA interfaces these days? Nope. But do you see floppy->USB interfances? Yup. So that's why I'd stick with a raw storage format like a floppy or SD card, and not stick to something with its own interface like IDE, SATA, or USB.