Details on Why WWE is Scaling Back on the Number of PPVs for 2018

According to backstage sources, the main reason why WWE decided to scale back on the number of PPVs for the year 2018 is because they thought running multiple events per month will lead to a noticeable increase in subscribers for the WWE Network, which of course did not.
Instead, the company was adding the extra expense of another major show without the added benefit of extra revenue, not to mention interest in those B-level PPVs wasn’t strong, especially for the SmackDown shows.
Source: Wrestling Observer Newsletter