Throughput speculation (Score 1)

While it would certainly be impressive if it delivered those numbers I strongly suspect that the final product will use a narrow set of heads and require multiple passes to fully access the tape. According to Wikipedia LTO 7 for example requires 112 passes to fully read or write a tape. Also, even if full width heads could be economically built it would be troublesome to sink or source data at that rate, and as far as I'm aware tape drives take a relatively long time to seek and restart streaming after a buffer under/over run.