Im sure that the best times for cryptocurrency have not yet come. In 2017, there was a peak of capitalization and cost of some cryptocurrencies, but their popularity was still very low. When cryptocurrencies will be increasingly used in the world, their price will increase significantly more.
Yes in 2017 it was not great but it was only in the peak price, The great will be only when it will become a global currency and it will be listed on all bigger stock exchanges and it will happen sooner in the coming future. From the next month the exchanges will start to list it.