My own guess is there is a 50% chance of it ever acheiving $20k, and then maybe not until 2020 at earliest.
You realize that statements like these are really conservative, and very long term bearish about bitcoin... which causes me to conclude that you have some lack of appreciation for bitcoin's potential upside.
I do agree with you that the higher the expected future price, the lower the probability that it is going to happen, but it seems to me that when you use words like "ever" in your prediction, you are attempting to predict too many legs in a chain of future events that you have to be nearly completely speculating about since it is nearly impossible to accurately predict more than a few legs into the future at a time... and the further out you go the more any prediction is going to be based on a lot of factors currently unknown.
Hopefully your bearishness is not rubbing too much off into me...

I entirely agree with you !
50% is the probability I am assigning. 'Ever' is not a prediction, just a part of one of the possibilities.
Of course, I omitted to say that another scenario (part of the other 50% if you like), is that $100k is achieved before 2022.
All these numbers and time frames are speculation, yes, and subject to evolving circumstance. That is what this thread is for.
Hopefully I can present ideas that give others food for thought, and also prevent ppl from making errors in trading by being too myopic. My apparent bearishness is only a comparitive with general bullishness, and the greatest mistake IMO would be too become too mentally committed to a bullish outlook (and thus disillusionment) when we are merely in a long bear market, which will eventually turn round.
Low predictions of $2-3k are merely realistic scenarios, and are helping to avoid the mental pain of HODling in a downtrand.