Sometimes it happens that altcoins are more profitable than Bitcoin, nor to deny that. Like investing coins that are in hypes gives us x2, x3, multiple times in general, and that is good.
If you are limited with highly reputed coins then you will get chances to remain profitable but if you extend your altcoin investments into random coins then you may burn your finger. Even some altcoins are highly profitable than bitcoins, I guess it will be too difficult to identify such coins and the right timing specific for that coin. This is the reason I never prefer go out of bitcoin investments.