ChatGPT is not a SaaS in the relevant sense, because, if you had a magic genie that could do the work of a hundred 99th-percentile software engineers for free, that would not suffice to let you clone it. You would also need to acquire tens of thousands of GPUs and put them to work training the foundation model, which reportedly would cost a billion dollars or more. LLMs are very unlikely to move the needle on this requirement even if they keep becoming more and more capable.

One could sort of analogize it in this respect to an IaaS like AWS rather than a SaaS; you're paying them a big monthly premium primarily so that you can avoid substantial physical capex, not to avoid the costs of software development.

(I agree that the post's framing is deeply silly in a number of respects; it's just that this specific objection doesn't go through.)