Every coin has its own problem and bitcoin as an innovative one so problem will surely occur every now and then. What's happening now is just pure manipulation in which whales are accumulating.
Having $4k for its bottom is actually a perfect time to buy.
Exactly because every useful coin must be tasted to know it's strength n value n one such method is economical push n pull on a coin, I also believe that much work n acceptance on bitcoin wont allow it to crash or become irrelevant