I'm sure I'll be ripped for this, but how can you say they are for COMPLETELY different markets? What are these markets you are talking about?
The Bold is aimed at the consumer market. I am sure they started work on it from day one aiming it at the consumer market. They did not alienate the corporate crowd by leaving something out, but make no mistake, its for consumers. That is why we have heard about the beautiful screen, improved media player, video recording, etc. RIM is counting on the corporate market to eat it up, but they are hoping the Bold takes another big step (following the Pearl and Curve) into the consumer market.
The iPhone is also aimed at the consumer market, but again, make no mistake, Apple is hoping to make a big splash in the corporate world. Hence all the hooplah about Exchange support.
I've been an avid Blackberry user for 2 years, with a one month break to try the iPhone last fall. I work at an Apple store and have for 3 years. 75% of my coworkers use the iPhone. 2 of my best friends use the iPhone (with who I camped for 3 days to get said phones), and 2 others use Blackberrys. I'm not sure which side of the one-sided experience I am on, or what extreme bias I have, but I absolutely believe the two are competing. Just because each should dominate their respective area doesn't mean they aren't butting heads to get in the others space.
Having said all that, I think numetheus' entertainment v. messaging assessment was spot on.
In short: iPhone trying to get Exchange and push email going added with Blackberry trying to improve the browser and media player = two competing devices in two different markets.