>Fellows on strikes are acutely aware of the risk of getting scooped every minute that is spent away from the bench, but in the balance, its really not foremost on many folks' minds beyond a point.
FWIW, most researchers I know who were involved in academic strikes did not put their research on hold, but all of them with teaching duties did walk out of that. This was sufficient to pressure the university to acquiesce to a decent portion of their demands, since total loss of graduate TAs/instructors is hugely consequential to the university. But the NIH is not a teaching institution, so this particular bargaining threat is moot.
>The assumption is that the movement has built enough support for everyone to strike together.
Perhaps we should agree to disagree on this, but per above, I maintain that this is an unlikely assumption at a pure research (i.e. non-teaching) institute.
>Mice get sick, chemical stocks go bad, collaborators leave for personal reasons, etc. etc.
These are all factors outside of an individual researcher's control. Few people would voluntarily decide to set back their career.
>Truth is, when it comes to transitioning to a faculty position (which is the point of a post-doc position), being scooped is really not that much of a deal
The point of a postdoc is to publish a handful (~1-3) of very high impact studies to bolster a faculty application. Getting scooped on even one of them can be a huge deal if it causes the publication to lose its impactfulness. I know several people in that boat, unfortunately—the scooping publication went to an absolute top-tier impact factory journal (e.g. Nature/Science), while the scooped paper went to a much lower impact factor speciality journal. Sadly, faculty applications are often evaluated based on the perceived prestige of the candidate's publications, not their actual contents, and while I can't say for sure that the scooped faculty candidates I know didn't get their ideal positions because they were scooped, I'd bet it was a nontrivial factor.