There is nothing preventing Apple from charging a single developer something different than a corporate one
Ok? It's Apple's decision on how to run their App Store. They believe running $99/year at a loss can be offset by 30% cut.
Instead of $99 per year it could also be $99 per month.
And a large company can submit 200 updates in a month, clearly making $99/mo not enough.
"Charge $9/submission"
Then what if a developer like Facebook uses Apple Maps for their 1 billion customers?
"Charge $100 per 1 million users of Apple Maps"
The list goes on and on and on, making the developer program confusing, more expensive for indie developers, and less appealing to new devs.
Not a valid solution.