Pretty much this. There's a lot that's up in the air for WFB, and until we actually SEE 9th, few rumormongers want to touch it.
Meanwhile, 40k is introducing new factions and new supplements, dropping models like they're hot.
And they are hot.
Edit: Also, I have a strong feeling it'll just be a matter of time before Steve the Warboss is proved wrong on a few of these details by other, more reliable rumormongers, or otherwise just the release schedule itself. This seems so much like regurgitated rumor reverb rather than actual fresh information. If he had any new information, he might know what the 'Warhammer Content' actually is :I