Amazon isn't a thousand times bigger. And you cant link the price lowering to Dell. It's not as simple as that.
Yes, there is the Ecuador complete ban, and the regulation over mining in USA. Enough to cause a $20 drop.
Its impossible to especulate what would happens. I think the following will happens at the same time:
-More people will know what bitcoin is and get some thinking bitcoin price will rise after Amazon accepting it.
-People that knew about BTC will take it more seriously and get and hold some.
-People will sell their bitcoins thinking the sell pressure will make the price goes down due to the sell pressure(that theory is widely known and may drive many people's bahavior in such situation)
-People will un-hold some bitcoin to buy things, that will be converted to fiat and down the bitcoin price.
The strength of each factor will determine what the result will be in the short time, and I have no clue about that.