That's silly. Everything is limited by the scarcity of human attention spans, not just websites.
Shelf space refers to the market with which someone competes, not whether people are thinking of a candy bar or finding a bathroom or a facebook post. Your argument commits survivor bias because it's ignoring the millions of other websites that exist and are being used. Being popular does not mean something is a monopoly, nor does it mean there's limited shelf space.
Following your example, if Google spammed Pixel ads on it's home page, the page would become less popular. One of the reasons it became so popular was it's strict adherence to focusing on utility.
Even if true, what does that have to do with shelf space? Search results do not constitute the internet, and there are many more search engines than just Google.
Shelf space refers to the market with which someone competes, not whether people are thinking of a candy bar or finding a bathroom or a facebook post. Your argument commits survivor bias because it's ignoring the millions of other websites that exist and are being used. Being popular does not mean something is a monopoly, nor does it mean there's limited shelf space.
Following your example, if Google spammed Pixel ads on it's home page, the page would become less popular. One of the reasons it became so popular was it's strict adherence to focusing on utility.