I ought to be able to do better because I used to know more precisely how many dots per page are printed and how large they are.
But a back-of-the-envelope calculation suggested to me an upper limit of about 1000 kg to 10000 kg of extra toner per year in the United States. However, there are several factors that make me think that even the low figure is an overestimate.
I agree with your frustration about paying for this. Mako Hill used it as an example of an antifeature
https://wiki.mako.cc/Antifeatures
(It might be more accurate to define antifeatures in terms of buyers' willingness to pay to have the features removed, rather than sellers' insistence on being paid to remove them, since we can't, in fact, routinely pay for many of the antifeatures he mentions to be removed.)