7500? That seems high. Are there really that many unique TF characters?
While the number does seem a tad high - they didn't specifically say "unique" robots - so I would be willing to bet that repaints play a pretty big role in that count.
Think about the Energon Bruticus Maximus, Constructicon Maximus and Superion Maximus sets - those were all re-released with new decos, so that right there accounts for 30 robots out of the past 25 years.
I would be willing to bet that even things like the reissues of the Insecticons accounts for another three robots in that tally, even though they are straight-up reissues of figures from 1986.
Combine that with the fact that under the Transformers: Universe line, they also released the Sixtrain and Sixbuilder sets that were from the early 90s in Japan and then re-released by Japan in the early part of this decade.
From this past movie year, I think there were way more than 30 robots, if you think about all of the Transformers: Legends releases, the Scout-class releases, the Scout-class repaint exclusives to places like WalMart and Target, the Deluxe class, the Voyager class and the three Leader class robots, I would estimate that there were somewhere between 50 and 60 robots for this year alone - at that's just the Revenge of the Fallen stuff, there were also the Transformers: Animated and Transformers: Universe releases too.
Lastly, since Hasbro views Takara as their partner in the Transformers line, even in the years when here in the US we got very few figures, they were still going pretty strong in Japan, so I wouldn't be very surprised to see that they are also factoring in the Takara releases.
So again, like I said in the beginning, 7500 does seem a little high - if they had said something like 2500, then I might actually believe it averaging out to about 100 robots released each year.