Because a healthy portfolio is distributed not only in the amount of risk (I.e. low vs high risk) but also in economic sectors (I.e. tech/futurism, health, ener

Because a healthy portfolio is distributed not only in the amount of risk (I.e. low vs high risk) but also in economic sectors (I.e. tech/futurism, health, energy, agriculture). For any given investor, the decision to invest in Instacart or any other "crazy bet" is not made in isolation, but within the context of their existing portfolio, which means that the same investor could rationally decide to either invest or not invest, because that decision depends on the rest of their portfolio. Back-of-the-envelope calculations on HN are always calculated in isolation.