Those are all still assumptions; we can never be too certain about when the bitcoin price will hit $100,000. Saying this year or next year means you are also not sure about when that will happen, which is just the same thing as what @apogio is saying.
 
Over the years, we can only get a close prediction of what the price might be, but getting the actual price, which it will be at a particular time, is always hard to predict, and that's how bitcoin has been over the years. The price is always, to some point, predictable, and we just have to accept that.
 
The only thing is that the value will always be the same, as the figure is not reducing; just the exchange price going up and down makes it harder for its price to be determined.