Approved by the FDA in 2005. Probably took a while for it to become widespread.
The thing is: The protocol for a positive skin test wasn't "Here, take this 9 month treatment." It was "You need a chest X-Ray to show it's not active. If not, you're good to go!" Especially if they know you've received the vaccine. And no one should have made you go through the treatment multiple times - it's pointless, because even if you never had the vaccine but had latent/active TB, you will always test positive with the skin test. Knowing you'd gone through treatment once should have sufficed.
I know a nurse who definitely has latent TB (i.e. no vaccine). And she never had problems after a positive skin test - her employers always knew about it and as long as she had a clean chest X-Ray, she was deemed fit to interact with (at risk) patients.
Whoever made you go through treatment was incompetent.
To be clear I never went through the treatment, it just took a lot of arguing with doctors and the school/nonprofit administration in question after the false positive. I never had a chest xray either, I just had to drill it into their heads that Soviets got the vaccine and that it causes a false positive.
It sounds like they weren’t very well informed of TB protocol.
I last had one in the late 2000s