A 64GB SD card would be more like 700 TB of writes. That should be sufficient for a decade of usage for the blockchain even if the tx volume increases by a factor of ten.
And fast storage tech 10 years hence will not have the capacity and cell programming limitations of present-day flash technology. This sort of factor is never accounted for when arguments are made against the scalability of the blockchain. But significant near-term breakthroughs in both mechanical and solid state storage are mature enough to hit the market this year and next, and this is after both technologies have been bumping their heads against a ceiling for a couple of years now.