WordPress blogs being targetted for deindexing

It appears that google is aware that most link sellers are using wordpress blogs as they are extremely profitable, so mainly wordpress blogs are being targetted for deindexing. Now ad networks are finding it difficult to get websites, especially wordpress blogs, despite offering a bonus for adding the blog. Now getting domains with DA 15+ has become extremely difficult and there is a risk that the domain will get deindexed.
One ad network paid bonuses of $50K last year for adding wordpress blogs and within a year, almost all the blogs are deindexed, making it impossible to make any money from some ad networks. The domain investor will also face a loss.
Earlier 10% of the blogs were deindexed, now 50-60 % are getting deindexed and their DA is also decreasing, so link sellers are leaving the market, working offline will be more lucrative