The past Bitcoin bubbles were in different time with a totally different situation than today. The last major bubble was in 2013 when Bitcoin made up 95% of the market. Then if Bitcoin crashed everything else did too b/c alt coins then were a mere 5% of the market. This time around the industry is much more mature with "safer" more liquid exchanges with ability to short. Coins like Ripple & Steller that recently made artificial moves pumped by insiders with over 50% of holdings will crash over the summer. Good fundamental coins like ETH and BTC will con't to make new ATHs this year as their networks effects kick in stronger and stronger leading to sustained longterm growth.