The post details how yearly subscriptions is one of the major issues, not monthly ones. There is already an update to monthly prices from 1.99 to 5.99, but the people on the yearly subscription locked in 0.99 or something like that.

The 30 day window was not enough time to rectify that and would cost him 50k in the first month to cover the diff. The author suggested he needed at least 3 months to implement changes and switch at least some portion of yearly subscribers to a higher price.