It begins at 39 min and I found some other items noteworthy so I am going to do my own summary which expands on yours.
1) When he took over D&D he was told his teams goal was to double the size of D&D by 5 years. They doubled it in 3 years instead.
2) They were selling about as many PHB every year as were sold for MOST of the 3e era. And they were already 7 years in, selling more PHBs every year than most of 3e's entire run.
3) The story up until 5e was each new edition would have a fantastic first 2 years and would taper off at 5 to 8 years off and a new edition would be needed. That never happened with 5e and core book sales increased every year since 5e began.
4) The average campaign lasts about 6-8 months instead of years now, and so from a business perspective people buy more stuff as they cycle through campaigns. This was a change which the company first really noticed in the shift from 2e to 3e. It was a phenomenon first found out in 1997 and 1998 from TSR research, where the average campaign was 9-11 months already. But it took until the design of 5e to actually design an edition with that 6-8 month time frame in mind as much of what they did with 3e and 4e still apparently had longer campaigns in mind despite their own prior research indicating it was likely shorter. This is why 5e launch with "Here's your 6-9 month campaign in a single book" format. He thinks this was one of three main factors which accelerated D&D's growth. [See around 48-50 min mark]
5) The audience changed from 88% male to 50% male for 5e, which was not a reduction in men playing but a huge addition in females playing. This almost doubled the size of audience, in addition to high school boys and now high school girls, which was a big growth accelerator.
6) The ascendance of YouTube in teaching people how to play D&D was a big, probably biggest, growth factor for 5e because it made the game much more approachable. Before that point, it was either find an existing group or go buy these 3 textbook-sized books and teach yourself. Now, you're a high schooler who has heard of D&D and just watches a video to see what it's about and how it works. It also resulted in cross-pollination to other niche nerd interests people had who were perusing YouTube.
7) D&D was at a low point when 5e launched. 4e didn't find the audience it had hoped to. WOTC had dramatically scaled down the department for D&D after 4e and WOTC was considering tabling D&D at that time. Due to this, they published far fewer products on 5e launch. They still would have liked to do a publication every month they just didn't have the resources for it.
8) They discovered, accidentally, that by scaling down the number of products they published, the remaining books they did publish sold a lot more. In fact they were not losing in total sales by producing 3-4 books per year versus producing far more books per year. The prior TSR policy of selling 60 books per year was cannibalizing book sales from each other, and to some extent that had been still happening with 3e and even 4e. Even though they knew signs of this problem had been seen in 1998's surveys.
9) When he returned to D&D 5e, he was still under the impression it was operating as a "front-list driven" business, where they newest products you put out were almost all you sold. That had been the main theory under TSR and 3e, that the life cycle of products was 60-90 days. But 5e had rapidly become a "back-list driven" business. 65% to 70% of D&D sales are the products which had not just come out. New products accounted for just roughly 33% of the sales. Which led to no 5e WOTC products ever going out of print. Out of the Abyss, which is 10 years old at this point, is sill selling for WOTC. Which is an astounding change from prior editions. This change to a back-list business brought certainty, predictability, and health to the D&D business line. This change was so major it's the #1 thing which boosted D&D into this other realm of success.
10) Digital was the last major change and upswing for D&D. Sales of digital books on D&D Beyond are very high margin.
11) This combination of factors pushed D&D "well into the 9 figures".
12) OGL: The huge success of 5e attracted Hasbro executive attention. WOTC was, politely, disagreeing with them. The OGL was one of those points of contention. He was very pleased Hasbro reversed course so quickly after the OGL mistake. The council WOTC gives Hasbro is to recognize both D&D and MtG are unique business types and not normal product lines. There remains still a battle for the soul of D&D between WOTC and Hasbro but he's now optimistic that Hasbro is starting to understand the issues better.
13) Running the D&D team has become more complicated because they're no longer selling to a monolithic set of core audiences who want things like old school heavy Forgotten Realms lore (and it has become much harder to serve the older school core audience as D&D has grown.) For example, the largest growing segment of D&D sales is 11 to 13 year olds now, who come in with no background in D&D. The Team now has to think about so many different audiences and expectations when developing products than they used to have to consider.
14) The people in the D&D team are genuine fans of smaller publishers. He loves for example Pendragon. Everyone on the Team has interest in growing the whole industry and favorite smaller publishers.
15) Advice to smaller publishers is a) keep in mind the multitude of differing audiences now, and b) keep in mind the era is now digital focused if you want a larger audience. That includes remote play, like Roll20, and character creation.
16) D&D is now a major, important, strategic pillar for Hasbro and can no longer be that little thing over in the corner. It is now one of Hasbro's top 5 brands.
17) He calls out ENWorld, Advanced version of 5e impresses him. It's for too small a segment of the audience that WOTC couldn't sell that, but he likes it and hopes it's doing well. Also calls out all the heavier lore stuff selling on DM's Guild which he likes, and Keith Baker's pushing additional Eberron lore on DM's Guild, etc..
18) One of the big TSR mistakes was so many products they put out were dependent on other products. Example: put out Spelljammer, then a War expansion on Spelljammer, which is only for a segment of the larger audience. Then you put out adventures for that expansion, which reduces your audience again. Half their products under TSR became two or three levels deep in dependency in prior books. That didn't serve new fans well. The original Greyhawk map and vague description outline served new audiences better than the product dependency model that TSR eventually pursued. Products need to be self-contained things to be friendly for new players. This, despite designers liking to do more and more deep lore.
19) He is confident D&D will see another 50 years.
