~ so future news from Tesla and Amazon will shake up the market more than once 
~ Bitcoin doesn't care about Tesla and Amazon news but investors do. And those who manipulate the market know that very well.
Bitcoin itself may not, but the people who hold bitcoin or will buy bitcoin do care about them. ~
~ Amazon is the biggest online retailer (outside of China) and if people see that it favors certain payment methods that they can invest in - the masses will flock to it. Some people might have little faith in Bitcoin but a big name like Amazon lends it a huge reputation boost if there is even a hint of "endorsement".
Wait, wait, wait, waaaait, guys!
Now I'm completely confused. When it is said that "Bitcoin doesn't care" about a thing, Doesn't it imply that, in fact, Bitcoin investors don't care about that thing?
OP's point is that "big news", like Amazon/Tesla accepting/rejecting Bitcoin can affect the market only short term, and I personally agree with this. Don't you?