What it seems like they really need is some general black-box testing time to try and better identify what is going on, along with looking at logs from devices

What it seems like they really need is some general black-box testing time to try and better identify what is going on, along with looking at logs from devices of users who had the problem. A screened room with a few devices and a simulator seems like a good resource to have, and it's a reasonable thing to procure at a center or two if they don't have it. It just costs several tens of thousands, not $10k. It seems like at this point 911 usually works on Pixel, and there's probably even good unit test and automated integration test of a lot of the components-- prearranged test calls with a given carrier's 911 impl isn't likely to fix it. But "usually" isn't good enough: Google needs to actually figure out what's going on, no matter what.