If this were the case for the majority of investors post demo day, how are so many YC companies raising money even if the start fund / YC fund partners are not

If this were the case for the majority of investors post demo day, how are so many YC companies raising money even if the start fund / YC fund partners are not investing a second time? My impression is most investors view the Start Fund / YC Fund instant investments as "free money" for the startups, and they view those investment partners as hedging their bets with YC as a whole. While I see your point, I don't think it's ever been an issue for anyone (as far as I've heard and personally experienced). I think the unfair early advantage these third party investors had is the real issue here, and much more in-line with changes YC has made in the past