"But those startups that are able to harness the productivity gains to deliver more complete and polished solutions that solve real problems for their users will be unstoppable."

They'd be unstoppable irrespective of LLMs. Why do you think Zuckerberg acquired Instagram? He literally tried copying it and failed. Instagram at the time was absolutely tiny in terms of pure labour, relative to Facebook.

Most people on hacker news are missing the point. Productivity gains for the sake of perceived productivity gains is not what creates economic value. Its not the equivalent of a factory all of a sudden becoming more productive in producing more of the same stuff. Not comparable at all.