There are been times whereby we see some altcoins performing than bitcoin could attempt to, but that doesn't mean that the way they have taken to rise to such expect they wont still take same in coming down, the fear of missing out is what people are being scared with some of these altcoins, bitcoin market cap alone is far fetched compared to all altcoins we have, we may not be able to predict on what the future can have to offer us but we can also uses what we have now in predicting against the future offers, bitcoin is what we have now and we cant expect any other for now except there be such which can beat the market volume and capitalization of bitcoin.