Scrivener of Doom
Adventurer
Well, you are mistaken.
Here is their most recent, public, official chart. (snipped chart to save space) If, as you say, D&D is 1/15th of all of WOTC (and I think it's more than that myself, once you include licensing incomes), that puts it as a rather important segment of Hasbro.
Wow, I never realised how critical WotC was to Hasbro's revenues and, presumably, profits. Those M:tG revenues are figurative rivers of gold.
No wonder Wizards is being extended some time to try and get the D&D brand back together. Greg Leeds must have a fair bit of clout within Hasbro.