Sorry if my English isn't perfect but at least I can write a second languange.
If you were a Hasbro CEO and D&D is a brand with an increasing value... what would you do? The future of this industry is in the videogames and the media productions (movies and series). But these need time. The key is in good stories, the best stories, but you can't hire a troop of writters for a faster publication.
No worries, I wasn't sure if it was on purpose or not.
If I was the CEO of Hasbro... there is an expression in English, "If it 'aint broke, don't fix it." Meaning, if something is doing well, don't try to improve it to much as you may actually make it worse.
D&D is one of Hasbro's most successful brands right now. So if I was CEO of Hasbro, I would recognize that the folks at WotC are doing a great job handling the brand on their own, and wouldn't try to influence their development very much by pushing for the cross-overs and product tie-ins you frequently mention. I think the gradual development of a film, and the limited amount of tie-ins they've released with video games and toys, are enough milking of revenue without risking over-saturation of products.
Essentially, if I was CEO of Hasbro, my focus would be on improving the struggling brands that are not D&D, or the development of entirely new ones.
I also do not agree that the future of RPGs is in video games and media. That was the consensus years ago, and D&D's pursuit of being "more like a video game" actually led to it struggling against rivals like Pathfinder. D&D 5E has been extremely successful because of its simplicity and ease of access for new players, and its limited releases allow for a higher quality of product.
If you look at Warhammer and how it pursues its licensing strategy (it gives out its license to any game company who wants it), it doesn't seem to have largely impacted its sales; instead, its recent success is more tied to recent improvements in their products, rules, and games.