I sold almost all altcoins and always do so with a large growth of the BTC. It's never too late to buy it back.
The price of bitcoin increased drastically and other altcoins were left behind.
Thus its normal for other crypto enthusiasts to think its wise to switch their altcoins to bitcoin but IMO I wont sell everything especially if you are holding eth, litecoin and bitcoin cash.
These coins has potential and will grow in the future, it takes time so be patient.