The next sentence is “in other cases, our partners had already run out of spaces on the year’s Schedule D and feared that another entry would require them to attach a separate sheet.”

Investors are in the business of buying things that don't yet exist.

Sure, they might do spreadsheet analysis and business planning to show the first person to invent a working, practical <foo> will make billions. But is this the company that will invent that?

That is an inherently vibe-heavy judgement.

I can well believe they remember considering a load of things, including the competition from their buddy's new venture firm. And they don't know themselves quite how they weighted the many things that contributed to the vibes, but they know saying 'generosity' sounds better than saying 'I didn't like the guy's glasses'