Many altcoin prices declined 90-95% from their 2017-18 ATH so even if trading volumes remained steady, revenue would have declined by a similar percentage. Being an altcoin exchange (no /fiat, or /stablecoin pairs), Shapeshift would have been hit especially hard.

There was so much growth in 2017 that most exchanges were likely severely understaffed at the 2017 ATH and were understaffed for most of that year and even in the beginning of 2018.