It might be rational. Supposedly, they are looking for 10X-30X. If they expect a >20% chance at a 15X return or some variation of that. Also their strategy may

It might be rational. Supposedly, they are looking for 10X-30X. If they expect a >20% chance at a 15X return or some variation of that. Also their strategy may be to not make decisions 'as they go'. That eliminates the need to actually be able to make the above estimate, something that probably requires a bit of an understanding of the specific business. They might not expect to do much better by making decisions on the fly then they would by following a simple rule, not enough to justify all of the analysis time. They might expect to do better this way, like rule based stock market investing. When it comes down to it, it's not really an issue with 'the VCs are dumb.' They may have been. But if so, only slightly. They also may not have been. The bigger issue is the discrepancy in risk tolerance. That's not really news.