- economies of scale no longer work, and you end up doing a custom ERP for your business from scratch.

- your business changes might invalidate your model quickly. You sell through distributors, but open an online shop -- and suddenly your customer is not one of few dozen well-known businesses with a known address and tax number, but user2252 who bought something late at night last night. And you want to understand the needs and behaviors of both.

- for the economies of scale, you might develop your custom solution 20x faster now, but you're still in competition with the established provides with templates for most of the cases (who btw have the same LLM capability at their disposal)

- for the change in business -- you can ask an LLM which changes this induces, and it will give you most typical impacts. And then you're back at square deciding if it's better to roll your custom DSL and the custom system downstream, or just use off-the-shelf stuff that covers 95% of it from day one (well, maybe day two or three)