See my 12:02 post above, and others around that time.
The App Store is a very different entity now compared to the way it was in the beginning. As I've said before, Apple needed Developers!!, Developers!!, Developers!! in the beginning to enable the success of a new computing platform, which was the iPhone, and eventually iOS devices. They needed all the "crazies" to "crawl out of the woodwork" to bring creative, and even bizarre (think iFart) ideas to the platform to see what could be done. Most of the "think outside the box" ideas came from small independent developers because well, working in a cubicle is the exact definition of being constrained to think from within an actual box.
Once Apple had its established iOS platform, it no longer needed the "crazies" (despite their "think different" marketing that celebrates them), so they went under "the bus". But, this presented Apple with a problem: they couldn't just throw developers under an actual bus (by just kicking anyone they wanted off the app store) because doing so would actually cause anti-trust headaches. So they had to invent a way to bury undesirable apps within the app store. They came up with Curation to accomplish this.
So today Apple has created a store where apps exist within "a blob". Apple has no duty to promote any apps in their store. However, Apple has every right to promote apps they believe will increase sales of their products. I get this, but it has consequences for developers:
1. If an iOS app can possibly be seen by Apple as increasing Apple DEVICE sales, then that app has a higher likelihood of favorable treatment within their curation system. This favorability can decrease marketing costs associated with the product.
2. If an iOS app does not meet criteria #1 above, then the entire marketing costs must be considered in the app business plan.
Keep in mind NONE of this apples to apps that are NOT a product. iOS apps that only exist as a service to sell something else are just that: a service and not a software product.