Relative investment and manpower on the issue has plummeted. I can't get into more specific details.

I can. Of course it plummeted since the end of the Cold War, but it raised again in the last 3 years, for obvious reasons. The US is lagging behind (not for long), but other nuclear powers are frantically resuming relevant activities.

maybe sometimes it is better to just stop learning more about a topic.

It isn't. Methods of learning might be unethical (and thus are not advisable to be pursued), but knowledge itself is beyond ethics.