Actual video of the event might not be that useful anyway, there seems to be a lot of witnesses to the accident. Unless there's something particularly unusual that was not sighted, like some sort of drone or alien interference the video will just confirm what is already apparent. In some cases I'd rather not have video of an event involving people dying that is plastered all over the news and internet for however long for no other reason than viewership and no real help to authorities.
WRT to LAHSO at major airports, it is only done with the supervision of ATC. Something goes awry the tower can issue go-rounds, stop instructions and vectors to assist in avoidance. ATC is also another set of eyes for the unknown factors, like rogue taxiing aircraft possibly entering a runway. There is also possibly a stagger factor for arrivals, and definitely conservative factoring additional to normal landing distance requirements.