> some patterns of speech are so recognizably LLM, i am convinced that the AI detection startups have a very strong chance to succeed on text.

The problem for them is the market. Those who actually want to buy AI detection tools usually want the impossible - detecting any kind of AI-written text, or even AI-written-human-edited text.

You're right in that many HN articles (not going to comment on this one specifically) are very easy to detect. But that's just because these article writers are too lazy to even use any of the plethora of tools that remove the smells automatically, or tools that write without them in the first place (I've made such a tool myself), or even just adjusting the prompt to write in a different style that avoids them.

Most people who would be interested in paying for AI detection tools want them to detect all of the above cases too, which is of course impossible.