I do agree that you don't make a dent, but it's a nihilistic point of view, because you're disregarding the ethics point of view. Sure, you don't make a dent in Amazon personally, but you make a conscious effort in your life to change something you don't like, which is significant and can't be quantified directly.

Also, I disagree that Uber will be around for decades, but it's primarily because of their finances.