I don't believe the blurb changes the context of the quote.
He was arguing that the all the important and fundamental laws of physics had been discovered. And so all that remained was to work out what was causing perturbations at increasingly esoteric degrees of precision. In other words that the future of science rested on refining previous discoveries, instead of the discovery of new revolutionary concepts. In the words of our OP here that, "all the science that is possible to do "at home" [is] already done."
Yet of course he made these comments just before physics would be completely revolutionized, and rapidly lead to revolutions in life as we know it. This was prior to relativity, prior to quantum mechanics, even prior to atomic models. The thing that makes it utterly ironic is making such comments at such a time after being an inadvertent key player in the discoveries to come.
Quantum theory didn't completely overrule how physics works at large length scales. Relativity didn't completely overrule how physics works at slow speeds & sub-planetary length scales. These are the 'apparent exceptions' to the laws of physics Michelson refers to, which lead to 'the discovery of other facts and laws whose action produces the apparent exceptions'. Validating both of those required 'extreme refinement in the science of measurement'. Look, for instance, at the 50 year effort required to validate the Bell Experiment.
Michelson further backs up this point in the next paragraph, where he provides several examples where precise measurements similarly lead to new science. Even more, look at his call to action: "Every means which facilitates accuracy in measurement is a possible factor in a future discovery".
His argument isn't dismissive of new science because it only leads to small differences in measurement. It's supportive of small measurements because it's required for new science.
He was arguing that the all the important and fundamental laws of physics had been discovered. And so all that remained was to work out what was causing perturbations at increasingly esoteric degrees of precision. In other words that the future of science rested on refining previous discoveries, instead of the discovery of new revolutionary concepts. In the words of our OP here that, "all the science that is possible to do "at home" [is] already done."
Yet of course he made these comments just before physics would be completely revolutionized, and rapidly lead to revolutions in life as we know it. This was prior to relativity, prior to quantum mechanics, even prior to atomic models. The thing that makes it utterly ironic is making such comments at such a time after being an inadvertent key player in the discoveries to come.