Yes, AI will struggle with doing full tasks unsupervised. But it can still do most of the work for many tasks. It just needs supervision by someone who understands the task. Sometimes the problem is the AI making incorrect assumptions about the task (it wasn't fully framed), sometimes as stated in the summary, the AI context window is too small, so it forgets things, and sometimes it just chooses a really bad approach.
I have been using Claude Code a lot recently. It's really good at summarizing existing code. It's good at specific targeted changes. It's pretty bad at designing solutions. I find that while it's usually still faster than doing it manually, I often have to point out where there's a better (usually simpler) solution.
So AI doesn't replace the human, but when used correctly, it makes the human more productive. If instead of having a human do the task manually and compare that to the time taken for a human to supervise AI doing the task, you'll probably find for many that the human can do a lot more with AI. (Yes, I know some studies have shown the opposite, but I think that's mostly people not understanding how to effectively manage AI, which may take some experience and training.)
But AI is far better at almost everything that it was a year ago. So even if it's 2.5% now, it may be 25% next year and 90% a year later. We're living in interesting times.