Isn't it more a question of what instructions those existing police officers are given? Currently their activities always come a bit late for the innocent dead and injured. A positive check about someone hiring a van is not prima facie evidence of intent to mow down pedestrians.

Comparing

- Running investigations, police officers being known and trusted "faces" in their community, and surveilling people in meatspace

To

- Running grep on every TCP packet of 65 million people, then asking a relatively small number of LEOs to "do something" when analysts see something that could be suspicious

The former seems more likely (to me) to succeed.

Yes, but that would require rolling back some of those cuts. Another thing that would really help is if police officers would make a half decent salary. That would also cut back significantly on corruption.