The irony that the top developers started as indie developers for the most part, and simply grew their business with successful products seems to be lost on the author.
Assuming that that's true (idk if it is), they were there first, when offerings were more limited and the big wigs hadn't gotten in. My little hypothetical appstore game isn't going to compete with offerings like Angry Birds into which probably many man-years have gone in already. OP's point is that it's harder to get in NOW.
When is this ever not the case? It's harder to own land now than it was when the government was giving it away for free. That in no way makes it impossible to own land, and no one says stupid things like "Why people can't win the land grab in America".
Build a good product, it will sell. Build an innovative product that scratches the itch of millions and you get onto the top 5 list.
What I see far too often is developers passing off a derivative or poorly executed idea, and complaining that the marketplace is the problem. It's not.
I don't see why you're looking at it as an either-or case. I'm sure there are plenty of poorly executed ideas in the marketplace, but that doesn't invalidate my point. To use your land analogy, it's now just getting more and more expensive to buy land in America - just as it's getting more and more expensive (in terms of cost and effort) to put out an application that meets the market's increasingly higher standards.
I'm not saying something is WRONG with the market, I'm making an observation about the state of the market.
There are a million apps, and only 5 people that can 'win' the app store at any time. To say it's more difficult to rocket to the top is an inane and obvious observation. It has nothing to do with indie development, it's about the fact that there are 5 top spots for one million apps. By definition, 99.999995% aren't going to win, regardless of whether they are indie or not.