No, a hack on Bitcoin does not mean that Litecoin gets hacked.  The technology is forked enough to keep all coins separated.  The mining pools are separated.  These two coins don't even use the same hashing algorithm. 

There's proof of work, proof of stake, delegated proof of stake, and more to come.
There's Smart contracts and there are blockchains and there are directed acyclic graphs.
There are ERC-20 protocols and SMT and lightning network and casper and plasma and segwit and sharding.

On and on it goes.  The technology is accelerating out of control because the technology funds itself and everyone is helping everyone in an open source environment.  

You are thinking about this topic in terms of corporate scarcity and this is a space of cooperative abundance.  

Bitcoin is not Google, Amazon, Ebay, or Facebook.  The big fish doesn't eat the small fish.  

Bitcoin is Linux, and there are hundreds of Linux operating systems.  None of them compete with each other.  That compliment one another.  This is the nature of open source collaboration.