Software VCs are so risk averse because startups have to find product market fit, which is already risky without throwing a bunch of tech risk on top of it.

That PMF bit is crucial: biotech VCs' don't follow that same pattern because they have relatively precise methods to identify product market fit, before the drug is even approved for sale. They have much more precise data on how many potential potential customers each drug could possibly have from public health data, how much they can afford from previous agreement and contracts with insurers combined with quality of life improvement estimates for the drug candidate, and a minimum of a 5 year monopoly which is usually closer to 14 years. Thanks to those factors, biotech companies have a damn-near-guaranteed exit strategy by phase 3 trials in the form of an acquisition or zero revenue IPO and the VCs can take much bigger risks.