I agree. However, the type of growth you're addressing here is different from the growth in social media companies. The growth in ad-tech based companies are by nature very artificial when put in economic terms. One can easily argue that these companies provide value by enhancing the reach and personalization of your marketing activities which results in increased sales and brand exposure. But at the very end of the day, how is an ever increasing of consumer spending GDP going to solve real life and death issues? Growth becomes relevant because capitalism is very focused on generating profit, you can either increase revenue or reduce cost, which one is easier? Increase revenue which then leads to, "let's get more users".