Nope. Just see the current scenario Bitcoin dips a bit, altcoins dip a lot only strong will survive.
Exactly, this trend tell us everything and what we exactly needed to do.
Altcoin being a threat to bitcoin is just an ambitious move of every altcoin as they're all dreaming that one day they will be on top. Nonetheless, no one will and ever replace on where bitcoin is. The fact that even a lot of bitcoin fork coins were born, trying to imitate what bitcoin had, they even won't touch the bottom of bitcoin.
Don't get confuse with altcoins, they were like a rotten ones in crypto sphere.
The argument that Bitcoin naysayers use is that Bitcoin is worthless because there are thousands of other coins out there that can be created. Peter Schiff tries arguing this point a lot. Erik Voorhees had the best response to it, which is, sure you can copy and paste the Bitcoin code and make thousands of crap coins, but you cannot copy and paste the community, infrastructure, and development team that supports Bitcoin.
So no OP, no other altcoin can threaten Bitcoins existence. Bitcoin will always be ahead because it is the reserve currency of the crypto space. It will eventually become a reserve commodity for the world. Governments will eventually be buying Bitcoin to hold in their reserves. Bitcoin is far too secure, and the network is far too large for another coin to take over. Nothing can replace Bitcoins killer app of being the most secure store of value outside of any third parties control.
Also, shouldn't this be in the altcoin discussion board? I could be wrong, maybe it fits in Bitcoin discussion since it isn't about any particular altcoin.