Because AI systems can and do and are being constantly tuned and developed and it's absolutely idiotic to look at the acceleration from "can barely step together a sentence" to "can code better than Barbos" in 5 years. This implies a velocity, and your view is looking at the state of the earth and saying that it will not continue advancing as such.
But can it really code at all?
Or it simply create an impression of coding by basically taking code from the internet which seems appropriate as a solution?
It can not code at any useful level, it's good for searching for useful snippets of code. It does not think any sense of the word.
It's just very complicated search engine trained to make appearance of intelligence.
You bought into this hype where they say AI is better at driving, better at speech recognition. When in reality it's not even close. It's useful as a search engine in fields where large amount of info need to be operated on. It can generate better than nothing subtitles. It can translate simple news text. But that does not imply thinking even at 5 year old level.