Sure it is loosing , Just look at the bitcoin price today , lossing , loosing and loosing.
as far as i know i think bitcoin now is most famous because a lot of people are working on it because of the price, price dump but it will increase .i dont think bitcoin losses its popularity now, they only think only but they dont know behind those things and it more getting famous now.
Bitcoin is sure the most popular cryptocurrency and it is not losing its popularity but gaining it. Even the negative things that happen to BTC (falls, bans, restrictions, hackers attacks) just add it fame.