I think the difference here might be the percentage of religious/educational institutions that survive > 1-2 centuries vs. the percentage of commercial ones tha

I think the difference here might be the percentage of religious/educational institutions that survive > 1-2 centuries vs. the percentage of commercial ones that do. It's not that corporations can't exist for that long. It's that they're much less likely to, and are thus a poorer bet for the survival of an extremely long-term project.