Or is it the other way around? People are putting attention to bitcoin (since it's the most popular cryptocurrency) and so it has a growing price. Bitcoin has the most user base than any other cryptocurrencies. It's really hard to say that bitcoin is the "best" cryptocurrency because feature-wise, it is surely not. All altcoin out there have their very own features that make them unique and better than other altcoins in some way. Altcoins even have a smaller transaction fee and a much better transaction time. There are times when the price of bitcoin is moving and everyone is trying to cash out.
Bitcoin is the most popular cryptocurrency because it's the base currency in the crypto world. You base the price of altcoin in the price of bitcoin. And sometimes even when the price of that certain altcoin in terms of bitcoin is down, and bitcoin is up, that altcoin's price didn't really move in terms of fiat. Basically bitcoin is affecting the price of all the coins. Of course there are coins that can be traded directly to fiat but converting to bitcoin first is still the dominant way of exchanging your altcoin to fiat.