After a huge amount of indian tax payer money was wasted by ntro to help google kill almost all link selling ad networks, now google is no longer deindexing websites of the link sellers
The domain investor has been closely monitoring the indexing and deindexing of her websites. In 2010-2017, when there was some money to be made selling text link ads, google was fairly aggressive in deindexing various websites, especially wordpress blogs.
In 2018, google has managed to kill almost all link selling ad networks, and also steal the correspondence of the link sellers, by bribing officials. So now it is no longer deindexing websites as it is aware that almost no links are being sold on the link sellers websites as webmasters are terrified of purchasing link ads. The websites which were deindexed in 2015 and earlier are also being indexed again as the websites are only an expense for the link sellers, they are not a source of revenue in any way.