We have some historical references:
- OD&D released Jan 1974, 1,000 copies. Sold 400 by summer, all 1,000 in 11 months. The second print run of 2,000 sold in 4 months. (Source of this and a couple of other figures is the highly recommended book Of Dice and Men
. Interesting to note that these initial sales of OD&D way back then are favorable when compared to the sales seen by small publishers in the present day.)
- In 1978 the AD&D Players Handbook sold 10,000 copies in first 3 months. (This is far stronger than most mid-size RPGs see in the same period of time in the current day. The highly successful Kickstarter for Numenera had 6,000+ physical orders, though exact numbers of core books aren't known from all sources in 2013. FATE Core and Accelerated had sold about 9,800 copies by Q2 2013 but over a longer time period (see their awesome quarterly reports). Dungeon World sold 2,600 sales both print and PDF in the first 5 months - see their web site for the figures.)
- Ryan Dancey on 1998 2E sales: "The one thing I can tell you is that when TSR did the transition from 1e to 2e in 1998, they sold 289,000 [2E] Player's Handbooks in 1998."
- But, the Acaeum says, in an article on print runs: "In 1989, TSR sold something like 1,000,000 copies of the D&D boxed set in one year. It was amazing." The article also estimates that in the 3E era they were selling "150,000 to 200,000 Players Handbooks per year".
- Marketing statistics, found in the 1992 TSR Catalog: "First-year release sales of the hardcover accessories average 170,000 units" (speaking of 2E AD&D hardcovers).
- "[3rd edition] was the most successful RPG published since the early years of 1st edition AD&D," Ryan Dancey said. "It outsold the core books of 2nd edition AD&D by a wide margin." "We sold 300,000 3e Players Handbooks in about 30 days. And the trajectory of the rest of the product line mimicked the PHB." - Ryan Dancey
- Of course, Dancey also says, "I have a confidential source who was one of the people making the decisions about strategy for D&D who confirmed to me that 3.5 was put into production because sales of 3.0 were "unsatisfactory". He says that 3.5 was always planned, but printed 2 years early because of those declining sales.
- Preorders for the core books of 4th edition of D&D in June 2008 were extremely strong and - without any hard sales numbers released by WoTC - anecdotal evidence from local game stores supported the claim that it sold much better than 3rd at launch. (My notes aren't clear, I think this came from Dancey as well)
- Very pertinent to what Mearls responded to me in that tweet, Dancey writes: "Then Wizards did it again with 4e. I have much less visibility into the 4e strategies than the 3.5e strategies but what I do know correlates very strongly with the idea that 3.5's "success" was brief - maybe more brief than the 3.0 window. Since 3.5 was essentially just a tune-up to 3.0, and it had not produced a result that was satisfactory, 4e had to be much much more than just 3.75 - logically you can't justify 3.75 if your goal is a substantially larger business than 3.5, since 3.5 didn't generate a substantially larger business than 3.0." He doesn't talk about Essentials, but looking at the way 4E changed approaches (dropping the initial "Power" series of books, releasing Essentials, etc.), it seems likely that the same issues were taking place with 4E as with 3E. (We can argue various edition-related differences, but it is honestly the same pattern regardless of one's personal preference for an edition over another).
Here's my take-away. D&D has a great history of ever-increasing initial sales. 5E continues that tradition, showing both the quality behind releases and the enormous strength of the brand. There is no question that 5E is flying off the shelves (both stores and online). Mearls saying that 5E is beating even the incredible initial 4E sales is not that surprising given how well players new and old are reacting to the edition. He notes that the key is sustainability. To date, no major RPG has figured out how to get an edition to keep selling without releasing tons of supplements that show ever-diminishing sales (because each supplement is of interest to only a smaller portion of the initial audience and is therefore less profitable). Diminishing sales eventually trigger a new edition. Avoiding diminishing returns and the need for a new edition is pretty much the holy grail for major RPGs.
One of the goals of 5E seems to be avoiding the need for another edition for a long time (in turn requiring sustained high sales). 5E doesn't approach this in a vacuum. There are many changes in how this D&D release is being approached. Where Dancey once talked about WotC's huge expensive staff compared to Paizo's, the reverse is now true. Many of the desired but not profitable products (minis, DM screens, etc.) are being licensed to other companies. There is also an attempt to compete with the larger entertainment space and to not focus much (at all?) on other RPGs as competitors. The argument goes that there are tons of customers for everyone if RPGs can successfully market outside its own space. This leaner D&D is still managing rave reviews and unparalleled quality, so it will be very interesting to see if 5E can keep sustained high sales longer than other editions and similar RPGs.
(I mention Dancey a lot, since he has shared a lot of information in the past. Like anyone else, he is wrong from time to time and his proclivity for sharing guarantees neither historical truth nor accurate forecasting of the future. Same goes for my perspectives - I've been wrong plenty of times too.)