In a ha-ha-only-serious way, I think this is a big part of the answer. DARPA is the only US funder that’s willing to pay for experienced staff. If your proposal

In a ha-ha-only-serious way, I think this is a big part of the answer. DARPA is the only US funder that’s willing to pay for experienced staff. If your proposal needs a half-dozen seasoned scientists or engineers, they’ll pay for it. In contrast, the NIH and NSF are very trainee-focused: a typical project consists of one professor loosely overseeing 1-3 “trainees”. We obviously need future scientists, but this model has a ton of drawbacks in terms of speed, quality, and even the nature of the project (which needs to let three people be somewhat-separately “evaluated”). It has also no room in it for any ICs more than four or five years post-PhD, which is bonkers given what the same organizations just paid to train them!