I am pretty sure if bitcoin reaches $100 then there would be more short sellers than buyers because at the first place it is really difficult for the investors to develop interest and trust in bitcoin and then falling from $400 to $100 again would certainly not be helpful for the bitcoin itself.
There would be the die hard hodls but the majority of people would be selling and cutting their losses maybe to leave bitcoin. So i think you are right. I would like to think i would have sold long before $100 and be in profit ready to throw a few dollars at it but not much and i am not waiting for $100 to buy much that is for sure.