>>...interventions are actually longevity-normalizing...

Reversion to the mean strikes again.

Given that we humans live longer than 'normal' primates, results might be more relevant if they were on mice strains bred to live longer than normal. Of course that could more than double the cost of lab studies, so it's probably a non-starter. For that matter... 900 days is a bit short of 3 years. Pet rats are known to live 2-3 years (longest lived one - in the Guiness Book - is 'Rodney' at 7 years) so a similar lifespan to the 900 days. If they just switched to rats, they could sidestep a lot of the genetic changes that have been done to lab mice. Probably a non-starter as well, for the same reason.