You're going to have a hard time debating that improved police techniques haven't made a difference at all, regardless of your personal opinion of Disney movies.
1. The methodology of collecting and reporting crime statistics has changed;
2. The use of said "improved police techniques" has discouraged people from reporting crimes;
3. The "justice" system has favored reducing its rate of Type I errors at the expense of increasing its Type II errors;
4. Enforcement of the laws is no longer consistent across and within jurisdictions;
5. There are more corrupt legal officials, and they are in better positions than ever before;
6. Social conditions and individual motivations have changed, and people are less inclined to commit crimes.
I'm not saying any of these are true, but they are all equally plausible explanations (as is any combination of them). You cannot establish a causal relationship by correlation (and "common sense") alone; you must identify all of the variables and control for them.
That's... debatable.
I think it's due to Disney movies.