I see this being at least a few years out. Performance is stil scaling up and cost is still scaling down. It’s going to require collecting a lot more specialized training data to produce fine tuned model. Business will need to adapt and people will need to learn how to accelerate themselves. But eventually, I see this going the way of the introduction of the computer to the office. No productive person will work without it.
As a thought exercise, I’m going to assume you’ve used same GPT model to produce some code before and been impressed in a narrow kind of way. Then project that forward a few years, through GPT-4 and GPT-5. Add some better training data and a better understanding of how to fit the LLM output into day-to-day work. Maybe add the ability to fine-tune on the existing code base and design documents. The trend-line is at least going to hit junior dev level, so the job will probably turn into a senior dev supervising a “team” of LLMs.