The WES system that sends broadcasts to cell phones is more like a pager than cell phone. On 9/11, a WES signal was never sent given the extensive media coverage.
The fact that you mention two way communication getting blocked during 9/11 as an argument for a technology that doesn’t allow 2-way communicatio… is kind of amusing.
There is a further, critical advantage to cells. The vast majority of people wouldn’t have to build a cell phone to get that alert. Pretty sure the only am radio in my house is an unplugged and stored hand crank emergency radio.
We all already have phones in our pockets, or at least in arms reach practically 24/7. The hardware to maintain the network already exists and is going to be maintained regardless if it’s used for alerts.
AM is largely going away. There’s only a handful of niche uses (like very rural or remote locations,) where it’s more useful.
To further expound on that…. Are you running your car or truck or what ever 24/7 in case of an emergency broadcast? In an emergency it’s best to have your vehicle be a dedicated vehicle and your receiver a dedicated receiver. You don’t want to find your battery ran down or that you’re out of fuel.
Which brings us back to… this bill is stupid. Unless you’re a trucker, you’re probably not going to be around your car enough to reliably get the emergency broadcast.
And truckers have better systems than AM radios for communication.