Accessing the tower is expensive in time, and equipment that runs at the tower is exposed to a wider variety of temperatures and RF stress than in a nice warehouse somewhere in the metro area.

It's possible the right caching at towers could reduce the backhaul bandwidth requirements, but seems iffy.

Not saying no here, just pointing out a very large concern.

My concern is cert/key management where the edge is somewhere you have very little control over, like a cell tower, random building network, or a users house. Even with keyless, once that device is in my home, Im pretty sure that entire thing can be reverse engineered. Not easy, like probes and oscilloscopes on exposed leads hard, but physical access is pretty much game over, no?

I've worked in this space and the solution is detection and mitigation. Limit the damage to single devices, workflow the user in, look for human attack patterns. Defense is futile.

How much latency do you think is incurred between the ISP and cell tower?

IMHO, I think it's mostly a solution in search of a problem. The internet backbone is fast enough to not be noticeable for end users. A centrally located server in the U.S. will have a maximum ping of 40 ms to anywhere in the U.S. That's faster than is perceptible to the end user. The only mainstream usage I can see is cloud gaming where ping is that critical.

Establishing a connection can require several round trips, and the latency adds up. "early termination" with a point of presence near your end user makes a pretty massive difference, especially if your user isn't on the same continent. Every additional 100ms costs amazon 1% of their revenue https://news.ycombinator.com/item?id=273900

I agree, I've been looking at discussion one here recently on how someone was working on the problem of "data storage at the edge" to compliment their "compute at the edge" offering. I think you can argue that that when you move compute and data storage to the edge you've effectively moved the data center to the edge. At some point if you put enough data at the edge you operating your own backbone makes economic sense and CDN don't maintain backbones they mostly buy paid peering and transit and try to leverage public peering wherever they can. I would even say edge compute is a solution in search of revenue stream and hedge in a heavily commoditized market.

(2) You can achieve 100-130 ms latency with a "like one data center per continent" sort of network. You don't need edge computing on hundreds or thousands of edge sites to achieve that.