Facebook's libra is an altcoin and also depends on bitcoin and it's investors. I don't think it will really affect the bitcoin's market price. Even the bitcoin is vulnerable, no one can surpass it even the other assets reach its peak. I really hoping that bitcoin will stay more longer because it's the future for everyone.
The libra looks unnecessarily centralized and raises a lot of questions for regulatory organizations because of facebook as a parent company. Facebook, due to its huge size, causes concern in many states. Therefore, the prospects for libra are not so bright. No wonder Facebook has so far limited itself to only internal payments on its social network.