It shows that maybe there was a flaw in Ryan Dancey's analysis of AD&D sales, dismissing Adventures perhaps too much.
I've always contended there were DEEP flaws in what he said (I don't think he actually analyzed anything, just spouted stuff to justify their approach. The splitting the lines statement was shown to be false rather quickly as they officially released Greyhawk, Forgotten Realms, and Eberron was in the making. IF they didn't want to split the campaign settings, they wouldn't have let every joe, dick, and harry design a campaign setting that could be officially under the 3e rules either (that would split a base FAR further than the number of campaign settings TSR had). They then had Kingdoms of Kalamar as an official setting but by other publishers. Then came Ghostwalk and Dragonlance as well as Oriental Adventures.
With all the campaign settings put out by 3rd parties that were published as officially supporting 3e (as per OGL or D20), there were MORE campaign worlds out for 3e and 3.5 that could split the line (and away from FR, or GH, or any other Campaign printed by WotC) than anything TSR EVER put out or EVER allowed.
I'm surprised people even still refer back to his statements as 3e showed that he was absolutely either not telling the truth, speaking out of the side of his mouth to decieve, exaggerating...OR...just didn't know what the heck he was talking about.
My thoughts...
THERE WAS something they learned though, and maybe that is what he meant to say. One of those things (I've mentioned other items elsewhere)...Look at these charts that have come out.
One of these was that the Core rulebook releases made money and normally were the top sellers. Even if it was a little, they still made money. Look at how they sold though. This is why 3.5 came out and why they were planning for a 4e EVEN BEFORE 3.5 was released. They saw the sales trend. If these charts showed anything, for sales they needed new releases. A campaign world a year was about right. You release a new set of rulebooks every 2-3 years if you could. That keeps the sales up.
This is what happened with 3e - 4e. You keep the rulebooks selling, with new releases. Everything else is to support that model. With the rules fresh, many settings will sell at a high number as well. When sales of the other books start to slump...make a new rulebook.
It's a cycle you can see with the books with the sales frontloaded. You want to keep the frontloaded sales up, and get a new frontload when they start to slump. Hence, already planning to have new editions when you are releasing the current one. You don't mention that to the fans exactly (I think Monte Cooke complained about this somewhere though), but that's what's going on in the background.
Of course, they didn't see that fans would get so upset either...
So here we are at 5e. It's kind of an anomaly if you look at it. Instead of the charts that we've seen here, there's that strong possibility that maybe that it didn't go into the slump quite so fast.
I think someone with a rather smart mind took a look at ideas of how 1e went and said, maybe if we tweak it just a little bit, we can keep the magic going. Afterall, even with all the troubles and such, OD&D, 1e, and 2e (and BX and BECMI) were essentially the same core system that kept going for over 20 years. It could be possible to recreate that magic, but keep the sales up for everything as well...
And well...here we are. Though the AE IS coming I may add...but then it may be more like a 1e to 2e than a new edition.