Big companies dominate much more in USA than Europe though, Europe has way more small local companies that compete with Amazon etc.
Also advertisements is more than just spending money, you need to mesh with the local culture as well. An American multinational doesn't really mesh well with most people and people reject their marketing, while local companies understand much better what the local people wants. In theory the giants could just hire locals, but in practice that has been really hard for them to do, as we can see every country has their own grocery store chains, brands etc.
Anyway, we can't refute all your points. It is really easy to just ask more and more questions, but at the end the results is what matters. And the real world results says that Europe is very good for small new businesses.