Certainly this isn't true at every level of granularity unless you're making some Penrosian claim about QM affecting say, one's decision tree? Which is a valid though quite disputed claim, say more about that if you believe it though.
Why not?
“~= 0” just means we likely will be unable to measure any effect. Not that there literally is no effect.
Us being unable to do science on something means we cannot scientifically state that it does not exist. Not that we can categorically state that it does not exist.