Pedantic note: Dicho, I wasn't querying the absence of the hyphen in "midwinter", I was questioning whether it's true to say of hyphens in general "They were standard in the 19C but for most words were gradually dropped through time." I don't fancy doing a count of words in dictionaries of the 19th century and the 21st to settle the point, but there still seem an awful lot around.

Of course, if you were a contestant in Countdown on TV, this kind of thing makes all the difference. Otherwise it seems pretty flexible. I mean, who cares if it's e-mail or email?