AI is getting better at writing code. However writing code is just some fraction of the work of many software engineers. AI doesn't work independently, it needs to be guided, its work needs to be reviewed, tested etc. There are some domains where it does better and some domains where it doesn't. There's a range of "AI" work between auto-complete style work, assisting in understanding a code base, and writing code from some spec or doing other types work.
All in all I would say it's a decent improvement to productivity for many situations. It's really hard to say how much and it's also not a zero sum game, as productivity improves there's more work.
Something to keep in mind is that if you look at a modern software project likely most of the code executing is not code written by the developers of that project. There's a huge stack of open source bits executing for almost any new project.
Specifically in OpenAI you also need to consider what type of software they are likely writing. Some of it may be more or less "vanilla" code and other is likely very specialized/performance critical. The vanilla code like API wrappers or simple front end pieces is likely more amenable to be written by AI whereas the more cutting edge algorithmic/scheduling/optimization work is almost certainly not done by AI. At least yet.
As software organizations become larger there's a lot of overhead and waste. It is possible that AI can enable smaller teams and that has a multiplicative effect because it lets you reduce that waste/overhead. There are likely also software engineers who will become better/adapt to new workflows and some who will not. It's really hard to say where things are going but overall my sense is that this like many other innovations will lead to more software and more jobs and not the other way around. There are many moving pieces here, not just AI itself but geopolitics, macro-economics, etc. Where are those new jobs going to get created, what new types of software/technology are going to be created etc. etc. History seems to show us that we'll adapt/evolve and grow.