I suppose I should have expected this. Back when we were switched over to NAS, their transition web site had something like the following:
Q: I used to be a customer of another ISP. When I was switched to CAIS, I was told that they were financially stable for the long term. How do I know this won't happen again with NAS?
A: NAS is its own backbone provider with a long-term growth plan.
Now, dear reader, I don't know what that says to you, but to me it has "not an answer" written all over it. I went and looked up the company's SEC filings. Their "long term growth plan" was to lose more than $100 million a year. Here we see the results.
I suppose I should take some consolation from the fact that COVAD has already been through bankruptcy once, has emerged, and is doing much the same business they were before with the same level of service. Still, this is one annoyance I didn't particularly need.