Well, it depends, basically the reason why altcoins are getting better before is because the investors are buying bitcoins in order to pay a project in return of their respective coins. That is the reason why altcoins are somehow shows the same trend to bitcoin before. Bu right now, we can say that altcoins would be stable as the market hypes from ICO's isn't worthy at all unlike in 2017.
Of course, you need to agree with your opinion, but first of all, you need to analyze the cryptocurrency market and determine the statistics of really high-quality and promising altcoins so that their value is real and not created due to the manipulation of speculators.