Marc Levoy (the brains behind Google's amazing Computational Photography technology), said that he had gone to the Camera companies before and they rejected his proposals. Camera companies were too afraid that someone was going to take a photo, and it would end up looking bad, and result in people returning their camera.
Source: Somewhere in this excellent course shared by Google: https://www.youtube.com/watch?v=y7HrM-fk_Rc&list=PL7ddpXYvFX...
All of the recent (4+ years) cameras have a "share to mobile" feature, where the camera acts as an AP, and your phone connects to pull photos from it. You can either pick the photos to transfer on the camera or on the phone, and it works pretty well for posting to social media, or instantly sharing.
I've run the RX100M3/M5 and a7iii off of USB power forever (a full day's worth of being a webcam via HDMI capture). You can get a battery eliminator for the older a7 models -- while it does require additional hardware and hassle, they do work, and can run off of USB.
The a7iii _finally_ supports some level of geotagging by using the GPS in your phone, and using a BLE connection to get location. It's not as good as a built in GPS, but it's better than recording a track log and syncing later.
I updated the -- again, full featured, but clunky -- remote app earlier and had to enter my account information using the camera 4-way stick, one letter at a time, as if it's 1995.
Edit -- forgot the best part: during the update, the camera locked up displaying "Updating, do not turn off". Lovely. (I turned it off -- removed the battery --, it still works.)
In the case of Nikon, the proprietary app for doing this was quite terrible, across all of their cameras that I tried it with. They released a firmware that opened up things up in the past year, though; better late than never. There have been brute-forced reverse-engineered alternative solutions but they have always been a pain to set up, use and maintain.
I suspect the other manufacturers' apps wouldn't be much better.
* No touch-id in the shutter button
* No cell phone connectivity / android app support to instantly share your photos to insta, fb, etc & to sync as you go.
* No ordering prints right in the camera
* No google pixel / iOS quality level HDR & night sight modes
* No GPS
* No braindead obvious webcam mode
* Most can't run off a usb cable indefinitely, unlike smartphones
* etc