Personally, I’d like to see the data/research behind the “3x” claim to buy it. Especially when it is hard to imagine Sam Altman as an unbiased observer when it comes to benefits of AI.
One angle to these multipliers would be this:
A generalist programmer can take other tasks of sw-engineering than just programming with the support of ChatGPT. Like DevOps, DBA and test-automation. For small team or company that is then actually saving or postponing FTE hires