Without derailing this thread too much, the US is quite a different culture when it comes to policing. Americans have accepted that they are all allowed to be armed to the teeth, and therefore it's perfectly "reasonable" for an officer to be tooled up like a paramilitary and to shoot first and ask questions later. That said, I completely agree that what the public will accept from their police can change, and keeping a very open discourse about what is and isn't acceptable is important. (And this bring us back to human rights and Brexit, right?)
On CCTV - it is mostly not "owned" by the police. That means it is not useful for every investigation (not pointed at the right spot, owner hasn't loaded film), although it can be used for quite a few.
Bodyworn IS owned by the police. And it is recording arrests/incidents, so it is pointing "at the right spot". (And officers like it because it tends to result in less violent arrests - even people who aren't thinking far enough ahead to NOT commit a crime because they might get caught DO refrain from lamping an arresting officer when they realise they can't claim self-defence. And vice versa, of course.)
The London Bridge jogger is a really irritating case, I agree. I don't think it tells you much about video in crime investigation though, except that if an officer can't find a match to a video or police drawing, then she can't bring a charge. In theory video/actual photo should make that easier than a police drawing from a witness (and we all know what witness memory is like), but it doesn't automatically mean you get your perp every time.