It's not so much a coincidence as an inevitability. Now that the money in the smart phone market is starting to reveal itself (both in products and in services) - as per the publishing of profits by choice iPhone developers, for instance - I can assure you that every website is chomping at the bit to develop a mobile footprint. Companies with a web presence would have to be insane to ignore growing user-demand for mobile content.
And so (this is directed to the thread starter), almost magically, websites are suddenly going mobile. Don't worry though most well developed websites have a link to the original XHTML version (which saves a cookie in Safari, meaning the next time you view the site you won't have to deal with a shotty mobile version. Even if firmware has something to do with it (in all likelihood, assuming it did, it was improved to better recognize websites that intended you to default to the mobile version all along), you can be sure that mobile browsing will improve - and that you'll still be able to choose full XHTML if you want.