The Duke's analysis of this issue, and many other issues on askaboutmoney has been excellent. If he changed his mind and came up with some analysis to show that Bitcoin was worth between $7,000 and $10,000, I would certainly sit up and take notice. I might not agree but I would be a lot less comfortable with my spreadbet.
I think the problem here is that you have a set view on what that analysis should be. There is plenty of analysis available to offer reasons as to why bitcoin has value. It is up to everyone up to decipher that analysis themselves and attach a monetary value should they wish to. Nobody has provided you with analysis that would make you consider bitcoin has value, that is fair enough. But that is wholly different from someone else taking the same analysis, or other analysis, and seeing value in it
I have read a fair amount about bitcoin and I am the first to admit that when it comes to the nitty-gritty tech side I am somewhat watery on its workings. However, I could say the same about satellite technology and its deliver of live football matches to my TV.
However, I do understand the concept of bitcoin and satellite TV. But understanding the concept in itself is insufficient to deliver real value. Instead, I rely on whether or not it the product, service or thing, is performing its functions. For satellite TV, that is obvious. For bitcoin, less obvious. So in order to find out I bought some, then I transferred some, then I bought some more, then I sold some, then I sold some more.
So in terms of performining its function as a decentralised, peer to peer trustless currency, it works. I see value in that.
Not that it is not without its problems, but it might be worth considering that before satellite TV was rolled out, black & white TV also had its problems. That said, the concept of transferring moving picture images into every home has real value and in turn the TV prevailed overcoming the challenges of picture distortions, aerial interference etc.
So is the concept of a decentralised currency like bitcoin sustainable? I think it is, but as has been alluded to by Negotiator there are other cryptos with superior technology coming on-stream.
Bitcoin may go to zero, nobody doubts that. But I doubt that it will go to zero because it is worthless today. It will go to zero if better technology replaces it.