I've been hearing similar comments a lot recently. People are very convinced that eth is likely to reach $1.5K until the end of 2018. I have missed the train on bitcoin to a certain extent, so I wouldn't want to feel the same regret with eth as well. However, I couldn't muster the courage to buy yet and I'm still monitoring closely.
You're looking at it the wrong way. A lot of people get tricked by only looking at the USD value of Ethereum. Right now one ether is being traded $450, that's an all time high (dollar-wise) but if you look at the ETH/BTC marked you would know that ethereum has been in a bear market since June 20th. The only reason why Ethereum's dollar value is going up right now is bitcoin. If Ethereum kept it's bitcoin value from June 20th one Ether would be worth approximatley $1,500. So you were better off keeping your money in bitcoin. No you didn't miss the train, get on while you still can.
It is impossible to miss the train of bitcoin. Until this year who missed all of 2013 we thought we'd missed the train.
Anything under $10,000 is still a very good entry point IMO. Bitcoin isn't a trillion dollar asset yet. Wait for the big money comes in, by that time you want to be in the game.