I remember reading an article that argued that it was basically a matter of being path dependent. The earliest steam engines that could do useful work were notoriously large and fuel-inefficient, which is why their first application was for pumps in coal mines - it effectively made the fuel problem moot and similarly their other limitations were not important in that context, while at the same time rising wages in UK made even those inefficient engines more affordable than manual labor. And then their use in that very narrow niche allowed them to be gradually improved to the point where they became suitable for other contexts as well.

But if that analogy holds, then LLM use in software development is the "new coal mines" where it will be perfected until it spills over into other areas. We're definitely not at the "Roman stage" anymore.