There is no absolutely and forever theory or truth, contemporary main stream physics in only a bunch of theories that can predict things that we observed better then other theories. GR is just a theory that predict the existing observations best. We cannot be 100% percent sure that GR(so is G which is part of GR) is valid in every corner in the universe, not sure even in every corner on earth, we only make a guess that it is highly possible that it is valid in every corner.
For the miracle you mentioned, maybe it already happened, e.g. sometimes ago at some place on earth, g is not 9.8 but 98, no body knows because we didn't make an observation at that time, even we happened to observe it, we will discard the data if it can't be further verified. Likely maybe it is happening now at some corner in universe or even earth. Maybe it will happens in some future days.
If the whole universe is just a simulation on some outer world computer which totally make sense, maybe someday the "person" in the outer world that creates the simulation program want to see what will happen if g is 98, then g becomes 98 suddenly in every corner in universe. If earth still exists at that time, we will all be doomed.
To the editors:this is more meta physics, but the question itself is meta physics. Please don't delete my answer which I wrote a lot.
@CuriousOne your answer is thoughtful but the author's point is to give reader a intuitive sense about g and don't need to deal with the details.