Yes. Steem power is measured by the number of steem a person is holding, this implies that should steem price go to zero, every upvote will worth nothing regardless of the amount of steem a person has. Anything multiplied by zero, gives zero, so there would be no value in upvote should steem reach the zero level. But I don't see that as a possibility. Steem price will never get to zero because of its design
Steem price greatly affect the worth of an upvote, that is why upvote get higher when price increase and lower when price falls. Thus, should steem price get to zero, one of the effects will be zero worth of upvote.
So should price get to zero, upvote will have zero value
In the past few days that the price of Steem is dipping, I never though that I would read a question that would say "zero".
That scares me a bit because if that will happen then our payout will also be "zero" and if that's the case it might turn this platform into a ghost town. I hope we don't reach to that point and be optimistic at this current situation of Steem.
If Steem goes to zero, the value of the payout on your posts will also automatically become zero. Do you know why your payout reduces each time Steem price reduces? It is because of the reduction in the price of Steem. So if Steem happens to go down to zero, it obviously means that the payout on your posts will automatically wipe away and would not reflect any $ on the post.