if no altcoin, may not be the trading coin that we know today. there may be, but there would be little option to redeem bitcoin with the existing currency.
That is right. The bitcoin is in demand because some people want to buy altcoins. For some altcoin, they can only do this with bitcoin.
I am sorry friend, I have different thought. I think people want to buy altcoins becouse they want to gain their bitcoin. Altcoin help bitcoin price to be stable.