Utopia literally translates to "no place."

What's your argument here? That working towards something perfect is inherently a waste of effort? It should not need to be pointed out that trying to change things for the better does not have to create a utopia to be beneficial. Reducing crime in non-militant ways (and therefore a reliance on police) does not need to remove crime to be a good thing to do.

I can reel off a list longer than recorded history of entirely unprecedented events of worldwide impact that have happened in the past few decades versus the past 5000.

The imagination being entertained here is your own; that humanity's future from this point could be even remotely similar to anything that's ever happened before.

Every choice we make as a whole now is of extreme importance, and almost nothing we can conceive of can be sensibly considered to be off the table.

This seems like a false equivalency between a given individual and the state: I can ask what weapons I'm allowed to have without asking what weapons the state is allowed to have.

No, that's the entire point of the statement. The debating of such things is counter to the stated goal weapons are purported to be brought into existence to achieve.

We don't stop people killing and harming each other by figuring out how to kill/harm them (or threaten to do so), by ever more powerful means.

We stop people killing each other by figuring out how to stop them (and us) wanting to do anything remotely like that in the first place.

Unless we change direction, we will end up where we're going.

Why is the police department the one working to make the police department obsolete? That seems like mistake number one if we're going to try to demilitarize the police.