Lisk doesn't depend on BTC. Infact Lisk relies as much on BTC as Ethereum does.

Lets be honest, BTC in terms of what it promotes, is an outdated coin that is slow and expensive for what it was designed to do. There are far better coins out there. The only real thing BTC has is it's name, which most people have heard of and have some understanding. Eventually BTC will be surpassed by something better.