It’s not about replacing all programmers. If one programmer with AI assistant can do work the same as 2 programmers then one position is redundant.

Even with self driving truck if one truck driver is leading another truck behind controlled by AI, and just for safety you have somewhere C&C center with one person monitoring 4 such ai trucks and in case unexpected event remotely take over control then one truck driver position is redundant.

While I do think there is some threshold where increased productivity makes positions redundant, I don't think 2x would do it in most orgs. My current team easily has enough work for us all to be 2x more productive.