Remember that compound growth is exponential. That's why logarithmic charts are so important for longer time frames! Otherwise any compound growth would look like a giant bubble about to pop and you'd be misled into missing out on easy money because of an elementary mistake.
Going forward, this has no reason to end now and i'll be staying until a reason comes up. 2018 should be a decent year and 2019 will lead the price to get towards the higher end of the long-term trend. For the end of 2019 and 2020: Either cryptocurrencies REALLY take off and crypto-based companies take over the nasdaq and we enter a giant crypto-based bubble, or we see a drop down to the lower part of the trend by about 30%. Probably the latter but my imagination prefers cryptogeddon :D
Remember why the index-fund bogleheads are so cocky: you can never predict the next crash very long before it happens and if you try, you lose 90% of the time. People have been predicting a nasdaq crash since 2012. Best thing to do is go long until there's a reason not to - and for us traders, it's to take the long approach in trades, look for the entries not the entries, and wait for a REASON not to. As you can see from looking at the logarithmic chart, the price is not a reason to be . Price is still just following the trend.