I’m only aware of two since the Great Depression:
Hawaiian Telecom - bought by private equity from Verizon in 2004. Too much debt, bankrupt in 2008. Reduced debt through bankruptcy and got new management. Sold to Cincinnati Bell in 2017
Fairpoint - bought Verizon’s northern New England operations in 2007. Too much debt. Bankrupt by 2009. Bought by Consolidated Communications in 2017.
Have there been any others? What worries me as a customer is that these other two seem to have only been in feeble shape for several years before bankruptcy. From comments here, it sounds like Windstream’s been a weak patient for years.
What happens to a really sick ILEC? People depend on it around here. Do they just shut down and an area lose phone service?