I think it's a combination of the two, but carriers definitely deserve a lot of the blame. As for Ars, they'd been getting increasingly snooty (reviewing increasingly expensive stuff, taking a more business-friendly slant), and they've always been Apple snobs. Basically snobs generally -- their focus is increasingly on stuff that I don't care about and certainly couldn't afford. But they really lost me when they uncritically reported that "solution" to the Voynich Manuscript when 2 minutes of digging showed that it was a press release for an upcoming book and that the author had no idea what he was talking about. It took them 2 days to post a follow-up, and longer than that to update the original article. I get that mistakes happen, but this wasn't that -- they never even looked to see if the piece was legit. (This is made even worse by the fact that one of the founders of Ars has a background in...wait for it...medieval Latin.)
I read Ars regularly and never picked up the slant you are seeing. I wonder if my perspective will change after hearing yours. Now that I think about a large portion of their device coverage I realize that they do like expensive shiny things. I'm sure that what they cover is heavily influenced by what gets clicks. Their coverage of cell phones in the $200-250 range is still excellent. I don't need a lot of phone but I want that dollar to go as far as it can, their coverage in that range is appreciated.
Their reviews can be good, but they have a tendency to bitch about something on an Android phone and then ignore the similar issue on an Apple one, for example. It's also a case of finding other sites I like better: I much prefer Techdirt and The Register at this point.