Why Aren’t Extended Timer Facilities Built-in to my DSLR?

On the weekend whilst photographing the limestone pavement on top of Malham cove in the Yorkshire Dales I lost my remote timer switch. It was dangling from my camera and got tangled up in my tripod legs as I was moving my tripod; one of the legs closed, snapped the timer cord out of the socket on the side of the camera which then disappeared down one of the deep grykes in the limestone pavement, never to be seen again. Thankfully it wasn’t an original (and very expensive) Canon TC-80N3 remote timer; my original TC-80N3 bit the dust last year when I managed to dangle it in salt water on a Scottish beach, this latest disaster was a only a considerably cheaper eBay clone.