Right now there are more coins available in the market which gives you more profit than bitcoin.
Bitcoin price is also not stable.
All these factors affect its popularity ??
What you think, still bitcoin is more popular ?
These factor can affect the popularity of bitcoin, if the price is not stable and very low, the users will try to find other coins like ethereum that is somehow related to bitcoin but bitcoin is still the most popular cryptocurrency coin that offer high profit to the users. Bitcoin will nit lose its popularity just becaus eof its fluctuations. Bitcoin users thinks that it is normal and they think that it is the best time to grab the opportunity to invest while the price is low.