Lower cost has made it much more likely that random bystanders have some level of video recording, rather than none; but entities with ample resources also take advantage of reduced costs, which is why, say, nontrivial areas of the developed world are effectively saturated with automated LPR systems. There is a win for those cases where it previously would have been the word of someone who counts vs. the word of some nobody; but elsewhere reduced costs and improve capabilities make having a big budget and legal power even more useful.
Improved surveillance only changes the game at the 'evidence' stage. If legal, public, or both, standards aren't sufficiently in your favor, improved evidence is anywhere from irrelevant to actively harmful. You can have all the evidence you want; but if the DA refuses to indict, or the 'viral' pile-on targets the victim rather than the aggressor, it doesn't help you much. Had McHenry's tirade been a bit cleverer, or her target a shade more unsympathetic, odds are good that the attendant in question would be being hounded as we speak.