why do people have emergency AM radios and not emergency AM scanner radio telegraph gadgets?

not sure if there is a more precise term. Basically, imagine a gadget that listens to one-way packet switched AM radio transmission. Ideally it should listen on a range of frequencies, like a “scanner”, and either save into memory or print out any text transmissions it gets. So if emergency transmissions were transmitted and received like this there wouldn’t have been the whole issue of waiting for the transmission, scanning frequencies manually, trying to understand garbled speech on a poor channel, taking notes while under stress and so on. Scanner would grab all transmissions automatically, even when people are busy, whereas the more compact nature of textual data would have allowed more redundant transmission that is less likely to get drowned out by noise.

Are there similar systems on the market already for some purpose, not necessarily emergency one?

Is there any sort of standard for emergency AM transmissions in the first place? In the sense that if there is one standard, maybe it could change towards better systems, whether the above-described or other improvements on the state of the art as of 1930.

Given the existing TV, radio, and various digital networks that already blanket the infosphere what would be a compelling reason to spend the resources to develop this capability? What us the unserved market?

Digital AM transmission can be (and has been) done, but AM radio is (all things considered) a pretty lo-fi medium for transmitting digital info compared to the alternatives.

The big advantage of AM radios is that they’re cheap. You can buy a little handheld one for less than 10 bucks, which is within most people’s emergency kit budgets. Even if you can get your gadget in the $20-30 range that’s going to price a lot of folks out. I also suspect that if you are going to make a pricier emergency radio system, AM probably isn’t the way to go.

in the USA there is the Emergency Alert System where radio and tv stations in every broadcast area send information appropriate for that area. so someone with AM, FM or TV device will get the information in every area covered by those services. included in the emergency information transmission is a digital code to turn on (and send an alarm) in devices equipped to receive it (weather radios, digital radios, digital tv).

(never mind)

to be more complete

the digital code in the message besides turning on the radio or tv for the message on those devices also contains data on the alert which shows on a text display.

the digital code in the alert will specify specific areas which can be as small as a part of a county.

As mentioned, weather alert radios perform some of the OP’s functions.
See the section on SAME.

So they don’t record or scan but they are typically band-specific and silent until an event occurs (or threatens).