I'm not sure if one specific reason would be more important than others. For instance, I wouldn't want to work on something that I'm not passionate about (ince

I'm not sure if one specific reason would be more important than others. For instance, I wouldn't want to work on something that I'm not passionate about (incentive B). However, over the long-term, I also wouldn't want to work on something that doesn't have a reasonable market (incentive A). imo your description of incentive A is mistaken.Thinking about the target market doesn't mean that "you only really care about making money". For example, many entrepreneurs would rather work on their startups than on something else that may think of as more lucrative. However, for the business to survive, the business needs to make money and so it a good entrepreneur would also try to understand the target market and think about whether it can sustain the business (and give up the business if it isn't able to make money).