On Thursday, June 10, 2021 at 5:32:36 PM UTC-4, bob lang wrote:
I installed knob and tube in the Cleveland area in the early 1960s. We started to add a green ground and that's what finally killed it. the cost increased by a third because of the ground and local jurisdictions also argued over the best way to splice the ground. Some allowed soldering while other insisted on a crimped connection.

--
For full context, visit https://www.homeownershub.com/mainte...op-291758-.htm

I would think it would have already been dead by then too, compared to Romex due to
cost, including labor to install. I know here in NJ I have not seen it in any new work in
buildings back to at least WWII.