You are correct, there are things that can negatively impact someone’s IQ. With respect to maximizing, I think the fact that people have been trying for decades to find something that reliably increases IQ, and everything leads to a dead-end means that we are pretty close to what’s achievable without revolutionary new technology. Maybe you aren’t at 100% of what’s achievable, but you’re probably at 95% (and of course percentages don’t really have any meaning here because there is no metric which grounds IQ in absolute terms).
You are correct, there are things that can negatively impact someone’s IQ. With respect to maximizing, I think the fact that people have been trying for decades to find something that reliably increases IQ, and everything leads to a dead-end means that we are pretty close to what’s achievable without revolutionary new technology. Maybe you aren’t at 100% of what’s achievable, but you’re probably at 95% (and of course percentages don’t really have any meaning here because there is no metric which grounds IQ in absolute terms).