And another thing: Smartphones! Are they the only cameras people will want in the future?
There are many alternatives to a D7200 or a D810. Some of them might be preferred because they are interesting photographically - a pinhole camera, or an 8 x 10 view camera, eg - others because they are convenient - a smartphone, eg.
During the fifteen years after 2000 anyone who wanted to take digital photographs had to buy a dedicated digital camera, even if they had no interest at all in photography. As a result, there was a dramatic expansion of the dedicated camera market: at the peak of sales, around 2010, annual camera sales were three times higher than in 1999 and six times higher than they were in 1985 (data at
https://petapixel.com/2015/04/09/this-is-what-the-history-of-camera-sales-looks-like-with-smartphones-included/). People no longer need to buy a dedicated digital camera to take photographs, even if they are not interested in photography, so they don't.
Will smartphones reach the point where they replace dedicated digital cameras for people who
are interested in photography? My guess is not. The reason for that guess is music: smartphones
could have replaced dedicated music reproduction systems even for people interested in sound quality, but they haven't because the manufacturers haven't bothered to give smartphones good sound quality because most people who listen to music on their phone don't care about sound quality.