I don't know if someone has tried to explain why, but if so, I'm sorry if it sounds like I'm repeating.
First off, you take a RISK whenever you purchase a new device, period. You can't always have the latest greatest thing at the time and not expect something better to come out later.
Second, this sounds like the iPhone price drop thing. Remember Jobs' letter? COME ON! Technology is always changing. My programming professor doesn't want us to buy books, why? Because they are out of date a day or two after being published.
Third, it's an optional update! You can purchase the software upgrade, but do you really need to? No! The iPhone is closer to a PDA than the Touch, so don't expect them to be nearly the same.
20 dollars for a upgrade of software that most people might not need. You can't really use the Map app when you're on the road, unless you are using a satellite car. The Stock and Weather apps are nice to have, but with the Stocks... It's easier to just use your computer for that. Email, same thing!
Don't get me wrong these apps might work for you in what you do, but for the general public, it's not necessary.
So if you think about it, it's a steal! 20 bucks to get you all the same apps the iPhone has WITHOUT THE MONTHLY FEES! So stop complaining.