Mark makes several good points.
A list of stuff that was once gadgets but that have been made reliable and are now routinely carried could include stoves, mattresses, flashlights, watches, water filters, lighters... heck, matches if you'd like to go that far back (but I'll leave those off my personal list, thanks). Time and refinement have earned them a place in our packs.
The initial post's focus is on digital devices but singling them out might simply be a product of our era and not a telling point of demarcation. Conversely, modern electronics have made many items better rather than worse--e.g., digital watches, solid state flashlights and digital radios perform better and are vastly more dependable than their predecessors.
There's sometimes a squeamishness about "relying on stuff that uses batteries" but that often seems like a canard. Yes, a gps can break or run out of juice. Likewise, a compass can be smashed and a map can be ripped out of a hand by a gale and blown to an adjacent county (ask me how I know). Isn't the important question always, "So, what's your plan when you don't have one of these any longer?"
I'll guess within three or four years backcountry communications will be largely resolved and no longer a question of whether there will be cell reception, whether SPOT will "phone home" or whether yuppies will have S&R running ragged being summoned by their PLBs. Then we can sterss over something completely new.