If 1 XEM = 1 USD, then NEM network would be worth 9 billion USD - it's more than BTC today. Everything is possible, but I have impression that unfortunately NEM is being undervalued by crypto community. Its closed source, and not easy to use for average Joe. Obviously I wish it was 1 USD cos I hold small stake just in case :-)
I think we will see $10 NEM.
1 XEM = $100 USD sounds about right.
Personally, I will be surprised if NEM doesn't eventually surpass NXT. And, if things break right, it could be much larger.