Theranos had a bunch of larger investors [1] many of them as sophisticated as any tech investor. I’m not saying SV investors are particularly dysfunctional, just that it’s pretty normal for tech DD to not get done, or get done badly. I use the Theranos example because it’s big and public (most disappear without any news).

[1] https://www.crunchbase.com/organization/theranos/investors/i...