I think DK has enough short-term randomness (much more than tennis or chess, for example) that for a one-day tournament, having one or two above-the-field competitors in there just makes things more interesting.
A couple other things: Estel's PB is 999,800, which of course is effectively a million. He was also invited to the KO2 but couldn't make it. For all intents and purposes, he's in exactly the same position as Ben, though he isn't technically at a million.
I would also add that several players in this contest are *capable* of a million points, they just haven't gotten it done because the right game hasn't come together yet.
Mike Grosbeck got to 923K, on pace for a million. He is obviously capable (you don't get 92.3% of the way there if you aren't!). Then you have players like Mitchell who have all the necessary skills, they just simply don't play often enough to close the deal. Getting that first million is a numbers game. You can be good enough to do it without having put in enough trials to actually do it.
And there's a big difference between players who've gotten a million or close to it on one or two occasions (Ben, Mike) and players who've done it dozens of times and/or who can sustain significantly higher pace (Dean, Hank).
I'd say that Ben is just about right in line with the top 3 or 4 players in this, all of whom are in that "close, or just over, once or twice" category.
Ross is really the only player who truly outclasses the field, but he should play too. It will be interesting to see if he can crush two of these in a row, or if Kong will be cruel that day!
The thing is, even though Ross is easily better than many players who have scored a million or more, as far as I know (and I may be wrong), Ross hasn't actually scored over a million! From what I've gathered, Ross pretty much always plays at full force/maximum risk right up to the end and doesn't care so much about actually completing the game, so he's never lived long enough to cash in the potential of games that are going at insane pace.
So, in reality, it's all a lot more complicated than the million-point cutoff. John and Eric are doing that, I think, simply because it's the simplest way of keeping the super-elite at bay.
The fact is, there's a wide range of ability in this tournament. It's unavoidable. There is a significant gap in skill between the best players, those in the middle, and those at the bottom. I don't think ensuring a level competitor field is the point here. Many will participate who have no shot at winning, and I think they're okay with that.