Revenue = subscriber revenue + ad revenue from ads shown to subscribers + ad revenue from ads shown to non-subscribers

The suggestions was to eliminate the middle piece and increase the subscription price to make up for it in the first piece. That's still leaves the last piece.

The above article also states that digital advertising revenue only accounted for 37 percent of total advertising revenue. So that means digital advertising revenue is at most 12% of total revenue. Furthermore, it is unstated how much of digital advertising revenue comes from paid subscribers vs unpaid visitors.

If we assumed, for the sake of argument, that half of digital advertising revenue was from paid and half unpaid, then cutting ads for paid subscribers would be doable with only about a 10% increase in price.