"Almost all" might have been exaggerating...but I maintain wireless DSLRs are common. At the very least, the option is available enough that anyone that cares about it can have it.
Random Google Search: of Techradar's top 10 list of full-frame DSLRs, 7 have Wi-Fi.
The cameras on the list you linked to with built in wifi are the Nikon D750, Nikon D5, Pentax K-1, Canon 6D. That's 4/10, which is better than I expected, but still pretty poor.
Random Google Search: of Techradar's top 10 list of full-frame DSLRs, 7 have Wi-Fi.
http://www.techradar.com/news/photography-video-capture/came...