Well, I stopped and started thinking what's so cool about mobile development and mobile apps, and I would like to share my thoughts.
Before modern smartphones, most software was written to be consumed in desktop environment, where the user was sitting in front of his computer interacting with it.
Smartphones make now easy doing something new: interacting with the environment the user belongs to. That is what I think is the most exciting thing of mobile dev. You have a bunch of information from all different sensors like gps, camera, accelerometers (and now nfc with android), and then you can mix them all and build whatever comes into your mind.
If this is not enough, you can even implement some service and put it somewhere in the internet, make your app a client of it and interact with other client applications.
It now takes a reasonable amount of time to implement something that before was seen as science fiction or 007 gadgets, like video calls or augmented reality or location based service.
I don't mean it couldn't be done before, but it's not an embedded stuff nieche with custom hardware and sensors anymore. With a 200$ smartphone and a 900$ laptop, you don't need anything else to implement a location based service with photosharing, istant messaging and all the stuff you want. And the new model of distribution makes easy to reach the users as well.
This just from a mere technical point of view, you obviously need a good recepit to mix all the ingredients and come out with a successful product.