A bull run will not always continue, nothing goes up without coming down, it is obtainable in every other market as it is found in crypto ecosystem. The bull market will come and the bear may occur, it is a normal market situations.
However, the 2020 bull market is gonna take a different market trends and will be a little better than the 2017 bull market trends. The bear market in 2017 was highly drastic and in my opinion, the bear market pattern will not repeat itself this time. After the bull run in 2017, the prices of coin/tokens dropped drastically within 7days which lead to the 2018 all time low. I think it gonna be completely different this time, every price fall may happen slowly and may move back steadily just as it increased slowly too.