is there any actual economic growth anywhere these days, that isn't an obvious bubble?
global real estate, cryptocurrency, the American stock market, chinese debt, american student debt, personal credit debt, subprime car loans, outstanding pension obligations, tech nonsense like tesla/snapchat et al... i'm certainly missing several more.
if you read the financial press, it's clear the investment class is acutely aware of how precarious and unsustainable everything is, but there is so much pressure to deliver short-term returns and so little opportunity for stable fundamentals-backed growth (see the withering of the bond market) that they are all regardless scrambling to extract every last penny until the music stops.
having already effectively eliminated interest rates for the last decade, central banks have no ideas beyond continuously pumping the system with yet more QE money - all of which is channeled toward offshore hoarding or short-term speculation rather than the meaningful investment on which QE is premised (which also belies the entire premise behind perpetual corporate tax cuts; large corporations are all already swimming in more capital and cheap credit then they could ever hope to productively use).
meanwhile, governments the world over adamantly refuse to increase long-term productivity - infrastructure, research, education etc - because despite the fact that many places now have literally negative interest rates, we're all still drunk on the patent nonsense that is
Laughter Curve austerity koolaid.
all of which means that when the far bigger series of cascading bubbles that emerged from our disastrous response to the last speculative crises inevitably gives way, there will be no monetary recourse - the emergency levers have already been deployed full-stop this entire time.
so although bitcoin is probably one of the more obvious bubbles to cast one's lot with, it's not like there's anything dramatically more sensible out there to invest in instead... and unlike everything else I listed, cryptocurrencies thrive on fake-news-lazy-teenage-libertarian-internet paranoia, which will not be in short supply after the second epic financial meltdown in as many decades.
good luck everyone... vault me! ; )