Today's 'tough' cameras have virtually no moving, mechanical parts as far as I am aware, excepting for perhaps the lens assembly which allows for zooming. Anything which has any sort of precision engineering, moving part will require some degree of care when handling. In my experience very few photographers (including most professionals) trat their cameras with anything other than respect, the possible exception being press photographers using cameras they are supplied with, and even then they tend to be careful because an obviously maltreated camera, broken when needed, does not go down well with editors.
I use housed cameras which have to withstand vibration, constant knocking around in various boats with waves and swell and are then with me as i drop into the water. So far none have had problems due to this and I've used Nikon, Canon, Fuji and Sony cameras in housings over nearly 40 years (and lots of Nikonos too). But not rangefinders because they don't work underwater. I've also used lots of M cameras over the years and again none have let me down except when damaged due to being dropped (and then only one - an M8 which worked fine but rattled). All my cameras are used but looked after.
So why the post? Well, I'm really not sure that many cameras lack the sturdiness they need for reasonable use. Certainly most seem to operate well enough and I've seen 'cheap' models used way beyond their use by date in terms of shutter actuation, etc..
Vents and Shadows by Neal Wellons, on Flickr
Tractor with my $9 Argus C3 by Neal Wellons, on Flickr
