> but presumably the VCs have some idea of what Thinking Machines is building
you imply that VCs are rational because bet their own money, which in current complicated world probably is not true. VC funds get money from complicated funnel likely including my/your retirement account and country public debt, VC managers likely receive bonuses for closed deals and not long term gains which may materialize in 10 years. So, investing 2B into non-existing product with unclear market fit/team/tech moat smells very strongly.
> you imply that VCs are rational because bet their own money, which in current complicated world probably is not true.
Correct. Most VCs are using someone else's money. See Softbank. And making extremely poor judgements on how to use that money.
Unfortunately in many cases those "other people" are, for instance, California's teachers.