I agree that losing the peg in the other direction, being unable to sell (from customer perspective) a NBT for $1 but for less would be much worse.
But I tend to disagree with your conclusion that you can’t lose all by losing the peg.
NuBits claims to provide a stable peg to the USD of 1:1.
It might not play much of a role why the peg was lost and that it was lost into an unproblematic direction (being above 1 USD per NBT).
It might be recognized as NuBits failed to keep the peg by those who don’t spend much time trying to understand what went wrong and why it wasn’t that bad at all.
Plus it will be displayed by competitors that NuBits failed to keep the peg.
It might be fallacious to equate volume with demand. But it’s fallacious to assume that there can’t be that much demand as well. Not long ago 30,000 BTC were sold. Imagine they had been sold for NBT instead of USD…
Not keeping the peg may cost enough reputation to ruin the whole experiment; this is my conclusion.