I had a look at CBRs estimated sales figures for September ( Sales Estimates for September, 2012 - DC Comics Zero Month Scores Big - Comic Book Resources ), and whilst Hellblazer came in at a little under 10,000 copies, the top selling Vertigo book (Fairest) is only shifting about double that. DC's top selling book (Batman) is shifting about 116,000. Mature readers books don't traditionally sell big (Walking Dead being the notable exception), and I'm pretty sure Vertigo has more or less always relied on books being perennial trade sellers rather than the monthly unit shifters. Yes, less than 10,000 seems low, but it's not like that's the whole story.
It's been obvious for a while the DC wants rid of Vertigo. It was pretty clear when Karen Berger didn't get a seat at the table when they had the management reshuffle. They've reincorporated all the former DCU Vertigo characters into the New 52, they've trimmed back on deals for creator owned books (to the point where otherwise rock solid DC man Grant Morrison is taking his creator owned stuff to Image), cut their range to almost nothing, and have Berger editing at least one New 52 book (Dial H). They've been winding it down slowly so as to not cause a fan outcry during a major transitional period for their big moneyspinners, but Vertigo is undoubtedly not long for this world. Tp be honest, on the balance of things, it's a minor miracle that Hellblazer is being allowed to go out on a milestone issue.
I believe you are over-reacting, but time will tell.
They have announced other books and miniseries will be coming out.
Care to elaborate - because I just looked at their latest solicits and there is absolutely nothing new except for an adaptation of Django Unchained (and I already made a post about Vertigo shifting from original material to adaptations)
Oh, and ironically, they have Hellblazer and Swamp Things trades on the latest solicit