Is that 50-100 million in revenue or profits? Compared to GWs consistent revenue of £120-130 million over the past couple of years, the latter figure seems unlikely to be reached, or even to be within reach. Though I suppose it depends on whether the book division is considered part of D&D or not, since I suspect that's a larger source of revenue than the RPG.
Revenue, surely. DDI appears to be bringing in around $6 million annually judging by the subscriber figures, and RPG book sales may bring in a similar amount. Fairly small beer, but novel sales are probably more significant. If Games Workshop(?) are taking in $200 million a year that's pretty impressive, comparable to fairly major software companies, and much more than any sums I've seen discussed for RPG companies.