I think there are a number of per-unit costs of software, because your edge cases get tested more frequently. The risk goes up for users finding bugs and incomp

I think there are a number of per-unit costs of software, because your edge cases get tested more frequently. The risk goes up for users finding bugs and incompatible working environments. They demand more unusual features. If successful, your growing user base attracts the attention of competitors. If coupled with hardware, the rising complexity of software makes the hardware more costly to develop and sustain. It may delay the introduction of newer or more valuable hardware features and products.