Most of the researchers are U.S. citizens, so in effect they are.
Also, most NIH-funded researchers have gotten quite used to continual budget cuts, uncertainty, and needing to make every cent count. "Expensive" does not equal wasteful.
Compared to what? What some folks in SV will blow $1.3 billion on?
Cohort studies like this one have led to some major advancements in our understanding of disease - if you know anyone who takes aspirin to reduce their risk of cardiovascular disease, for example, that came out of a cohort study. There is a tremendous amount we don't know about the development of diseases in childhood, life-course trajectories, the effects of environmental exposures that need well conducted, large sized studies - the large bit is important, as they need statistical power if anything will meaningfully change in terms of policy.
Also, most NIH-funded researchers have gotten quite used to continual budget cuts, uncertainty, and needing to make every cent count. "Expensive" does not equal wasteful.