I think they do. It can just be hard to tell from the outside.
An entire venture capital firm will certainly do more than 20 investments over the years.
- Most funds do about 20-30 investments per fund;
- And, each partner in each fund probably only does 4-6 investments per fund on average.
So most VCs are fairly concentrated, and either believe in the 20 slot rule concept, or back into it based on the way the VC investment model typically works.