Can't update to iOS 4.3

Question

Got my iPhone 4 from Verizon a couple months ago (even though it says "Verizon 3G" at the top of the screen). Been updating system software okay, until a couple days ago.
Currently have 4.2.10 (8E600) and was trying to download an app that, when I tried installing, said my system software was incompatible and that I needed 4.3.
So I sync up w/ my iTunes on my Macbook Pro, and click "check for update", and it tells me I'm up-to-date and that 4.2.10 is the most current version.
No error messages and posters above have already stated, it just says I'm already updated.
I updated my OS on my Macbook Pro and my iTunes, and my iPhone iOS still doesn't update to 4.3. What's up with that?!?!

Answer 1

Thanks for the replies. I kept doing research to see this whole Verizon fiasco and found this:
http://www.appolicious.com/finance/articles/8138-developer-ios-4-3-for-verizon-p robably-not-coming-anytime-soon
From the link above:
Not to be a naysayer, but there’s a name for some devices on a platform getting one update, while others get another: fragmentation. Yeah, that’s right, the problem that plagues Google's (GOOG) Android users and is supposed to be one of the big, great reasons to opt for Apple’s highly controlled iOS environment instead is now creeping into the world of the iPhone. And Apple only has two different devices to support, instead of the dozens available on the Android platform.
What’s more, even as Verizon users are getting a second-rate version of iOS, there’s talk that the merger between AT&T and T-Mobile will result in an iPhone for the newly acquired mobile carrier. That would make three carriers and potentially three versions of the iPhone. If that’s the case and Apple doesn’t get these iOS issues worked out (it’s in no way clear what might be holding back iOS 4.3 from Verizon, be the problem technical, business-related, or something else), fragmentation could be a word that comes up in the same sentence as the word “Apple” a lot more frequently.
Now, not sure how true this is but who knows what brand of thinking goes on during the decision-making of corporate execs.
One way or another though, it's clear this is a Verizon issue, which is IMO poor on either Apple's or Verizon's part and thus relegates us Verizon iPhoners to be completely at the mercy of either an obsure technological problem or someone's whim.