I thought for sure it would take until the end of 2018 but it looks like this summer ethereum might pass it up. With the turmoil around BTC potential splitting, it might be very soon. IMO this is healthy, we will always value bitcoin for being the one that started it all, but it's time for a more dynamic and adaptable currency to take the lead.
I am expecting that bitcoin will not remain that way, more coins are coming and expect that some promising project from ICO that may become popular too that will eventually see in the market. Let us see until when btc will exist, but as of now, i will invest more because the price is too low.
If you still have strong faith in the future of Bitcoin and you want to investing something for long term as few years, you can not find any opportunity better than investing into cryptocurrency (Bitcoin, Ethereum, Ripple, Monero, etc.) like now.
You should not investing money in any ICO, only trusted projects as KICKICO, The Abyss, Credits, Utrust you can invest money for long term as Bitcoin.