Yes it is, at least an important part. I'm buying very little in general, and it's either second hand or local most of the time - when I have to order things for repairs, farm or household, there's enough smaller online shops in my country or at least another European country. I despise big brands, big retail, big anything and try to stay away.
I'm blocking ads - and when I happen to see one on a friend's screen I'm confused - this is what people are putting up with between trying to read an article or listening to their music?