At what stage does just writing the code (which is getting easier and easier), just become the simpler thing to do?

It does in some cases, but modern software dev (in larger teams) is generally way too verbose (for my taste). The 'easier to do' you speak off will be heavily AI augmented, so it'll be the same thing. The verbosity; people want clear and descriptive variable names, function names, comments, docs, tests, etc which is a lot of typing and AI can do it from a few scraps of human text instead so I don't have to type it anymore.

Even if you are better at or find it simpler to write code (which I often do find), that's not true for 99.xxx% of humanity. I jury startups for incubators etc now and then and this month's cohort are often using chatgpt to do the software for their startup by one of the founders who 'did a little bit of coding in uni', but is not very good. The code they produce I would write far faster and better myself without chatgpt/copilot than they do with chatgpt, but I would do it even faster and better with chatgpt/copilot.

It’s quite simple. If you’re doing something niche (ie, it would be difficult to find similar examples online), and deals with highly critical code, it’s probably worthwhile to write it yourself, since there’s a high risk for it to produce bugs.

In my experience this was the case for writing a block driver & some other low level software.

It excels and arguably outperforms in some developers in other cases; app development, CRUD, and CS labs it finds on github. There’s still a risk for bugs, but an acceptable level considering the productivity enhancement IMO.