re: alerting telemetry - I'm not finding photos to cite right now, but I've absolutely seen "infrastructure" buildings (here in rural Ohio) with warning annunciators (lights and bells) on their exteriors along with signs reading "If this light is flashing call xxx." It's definitely a viable system for alerting.
I like your thinking and I try to espouse it myself (keeping things as simple as they can be-- keeping "technology" out of voting, not connecting things to networks that have no business being connected, etc). Short of a Battlestar Galactica-type "our machines rise up and try to kill us" event, though, I don't think the average person will ever understand the vulnerability inherent in networked computers or the risk/benefit tradeoff of connected vs. disconnected systems.
Even down at the level of local politics in a rural setting the "optics" of bringing technological solutions to bear on problems is seen as forward-thinking-- particularly when it "saves" the taxpayer money. I can't imagine trying to convince a local water board that moving away from a PLC-based system with a remote support vendor world fly, even citing this example.
This event will be another opportunity for more security vendors to cite in case studies justifying their products. More layers of garbage will build up on a foundation of protocols and design philosophies that grew up in an era of disconnected systems with lower stakes and a less complex threat model.
I don't see big money to be made in providing sensible levels of connectivity and security to this kind of infrastructure. I don't see industry stepping-up because of that. Maybe regulation is the answer, though I'd just expect regulatory capture to take over, and have it become another "PCI". Maybe a lot of people have to die before society takes it seriously, as has been the case with so many other safety codes over human history.
It makes me really sad, embarrassed for our industry, and more disappointed in human nature.