Yes, the price of bitcoin and eth in late 2017 and start of 2018 was indeed a bubble. One of the reason why eth price is down at 400 usd. Because some ICO's are selling there eth for fiat. Because we  need fiat currency to operate the business. And also the market is red again and bitcoin price is down. It make sense that eth will fall because eth/btc pairing is main trade of eth in market.