That's one side of the question, Ashley. Though what you say is true, let me add another viewpoint.
iDevices are all the rage these days, yes? Apple charges you 100$ a year to publish for them. Microsoft also for its W7 Marketplace.
Add that to the costs from AppMobi, you can see the costs scale pretty quick. As it is now, the service provided doesn't even allow any hobbyist to create a free game to release on the Android market and start making a name for himself.
Obviously you need to invest in order to gain, but it's better to understand that most Construct users are hobbyists and that is a lot of moolah. If I wanted to make a game and publish it to 3 devices, that would be almost half month's wage in a pop.
Of course, one can reason that you can take your time and publish for different devices/systems in different times, but that only makes it harder to capitalize after the hype is gone. There's a reason games are released at the same time for different consoles.
But let's hope contenders arise, though.