Maybe they have been by speculators, but if WotC sees the idea works, then they are going to publish more crossovers, if not for players at least for merchandising collectors. But if these becomes too important, then the D&D multiverse cosmology could be forced to some retcon to explain how characters from other universes could appear in D&D.
Once I joked about the idea of a Spelljammer/Fortnite crossover, but now seriously they would dare to do it to sell toys and merchandising.
More intercompany crossovers are possibles but the deals aren't easy, because they don't agree about relaunch and others.
I hope Hasbro is enough prudent to notice when a year of "thin-cows" (time of bad economy) could arrive, and I worry because this could happen very soon.
And they shouldn't "rest on their laurels". Here there are serious rivals, and not only Paizo, but other publishers of no-d20 TTRPG, for example Onyx Path and Chaisoum. Even their own workers is they aren't happy they could exit and create their own 3PP.
Other thread is Hasbro is like a girl like lot of "suitors" (Disney, Paramount, Netflix, Warner...). She can't choose only one, but all are necessary for the business, and there are good reasons to get engaged with nobody. And the most popular candidate from the high-school could become an outcast in a near future by fault of some wrong matter. Some rumors say a future Comcast+CBSViacom merger could be possible in the future to be a enough big fish in front of Disney, WarnerDiscovery, Amazon and Netflix. This means to start new negotations again. And don't reject the idea Hasbro wants to be also a mediatic empire like a second Disney.
Any suggestion? Hasbro shouldn't lose sight all the 3PPs with potential valious IPs. If these companies can't survive their brand could be acquired by others, maybe even powerful cinema producers awaiting to find a new gold-mine/cash-cow as Harry Potter, Games of Thrones or the Witcher.
Hasbro has said their strategy for the future is more focused on digital market, but AAA videogames are ambitious projects that need a lot of money and time. The D&D as TTRPG will be more like an idea laboratory to create new lines.