I think the same.
Altcoin to me is just a way to multiply my bitcoins, sometimes all my bitcoins are invested in a few altcoins but in the end i sell all of them for more bitcoins.
Well, I have the same thoughts. bitcoin is my primary currency too. but the growth of alternative crypto currency and their price's make me afraid about bitcoin. just see the price of Xaurum.. it almost beaten bitcoin in price. being exchanged for 1.2BTC each Xaur. and it is not only about the price it is matter of usage of altcoin. one altcoin may can't compete with bitcoin. but overall altcoin usage is growing over and over day by day. it is possible that one day people use other alts more than bitcoin,
just see the popularity of Steem, Waves, Lisk, not more than bitcoin yet but constantly growing like hill.