Negative things have been happening every year that I can remember for decades and it doesnt have to boost anything else because of it, it might just be a negative and less trade is done perhaps.    What is really needed to see a boost is the alternative currency option of BTC is genuinely offering a pathway for trade that is blocked elsewhere.    Brexit is largely just politics, ultimately the EU wont block trade with a nation that buys alot from it, they'll have to work out a deal to exchange goods just like EU does with every nation.  It would quite difficult to justify cutting off a nation that had exact same rules for decades and has only slightly varied while leaving the union, to say we will not do trade now would be a deliberate block not applied to any other nation and nonsense.   That scenario is self damaging as less trade done is less jobs within that nation.    
  How BTC can help with a political block of trade I dont know really, BTC is best suited to resolve digital goods rather then physical things like cars which are slow to transport anyway.

So 20k because negatives occur doesnt add up to me.   Most likely is inflation causing loose pricing in lots of assets, that is a negative from failing currency but its a gradual effect usually and there are many varied alternatives to FIAT, many assets besides BTC.