There are many reasons to not invest in a startup. Among others, these include concerns about the size of the market opportunity, the startup’s ability to capture value from its product, the competitive threat, the business model, and the investment terms.
Among potential reasons to pass, some are not related to the founder. For example, in the list above, this includes concerns about the investment terms.
However, most of the reasons to pass are in fact derivatives of the founder. In the list above, it’s the founder who decides to pursue a small opportunity, builds a startup in a part of the value chain that makes it difficult to capture value, is unlikely to be able to outperform competition, and is unable to build a strong business model.
So when you’re not investing in a startup for one of these reasons, which is most of the time, you’re not investing primarily because of the founder.