There are lot of crypto currencies that were created to compete with BTC
BTC lightning network is implementing due to the scalability issues the chain is experiencing with high 'fees' and transfer times..
If lightning network is implemented in Bitcoin will it destroys these competitors?
I do not think that the lightning network will change anything about the existence of altcoins. They will continue to exist and they will continue to try to solve the scalability problem in other ways. As long as there will be Bitcoin, there will be altcoins too.
