"The daily and stubborn reality for everybody building businesses on the strength of Web advertising is that the value of digital ads decreases every quarter"
The value of Google's ad network, including the average cost per click, increased for 14 years in a row, roughly speaking. Google certainly isn't suffering from any supposed value decrease per quarter, and if that effect were actually in place, their business would be nearly worthless by now.
Read the linked MIT article. There's a clear difference between Facebook-style display advertising, and Google-style search advertising. Google ads are much more profitable because people already have the intent to buy.
"The daily and stubborn reality for everybody building businesses on the strength of Web advertising is that the value of digital ads decreases every quarter"
The value of Google's ad network, including the average cost per click, increased for 14 years in a row, roughly speaking. Google certainly isn't suffering from any supposed value decrease per quarter, and if that effect were actually in place, their business would be nearly worthless by now.