You're right that the actual number is too low. But I think he, and Pine64, are just being responsible in managing expectations. The issue isn't just that the software isn't done, but also that the hardware may not be 100% there yet. This happens all the time with devices when something along the lines of 'oh crap, this power rail isn't stable in situation X and causes the device to reset' is discovered with pre-production hardware. The fix is usually trivial but often requires a PCB/component change.

I would absolutely have ordered one already if it sounded like the hardware were final... right now it merely sounds very, very close. The message I get from these warnings is the non-zero chance that there will be some annoying hardware issue that comes to light before going into volume production. This would not be unexpected since this is the first time a wider community is getting to work with it.