To ensure that only websites showing google adsense are making money online, google has very systematically deindexed all websites like Errors for showing other kinds of cpm advertising like bidvertiser. These websites are getting no visitors from google search.
If a website wishes to make money from the free search visitors, google will want the website to show google adsense or no ads at all.
As an experiment, the bidvertiser ads have been removed from one website and it remains to be seen whether the website will get indexed in google again, For a domain investor selling text link advertising, the money from text link ads will be far more than cpm and ppc advertising