I have relatives air-controller and pilots (me being neither) and we are all amazed at highly profitable airports operating in the first world w/o any sort on video surveillance pointing to the landing strips with the aim of capturing accidents during landing or take-off.
This in a world where a high-definition camera costs under $500 and DVR recorders can be had for under $200.
It's usually only low-resolution, wide angle video surveillance cameras that are deployed and then again only on a handfull of airports.
So many questions that would cost so little to answer.
Thankfully, this accident was recorded in video, so a few scenarios can be dissmissed off-hand such as any large visual explosions or large visual fires on any of the engines before the plane hitting the grown.
Unfortunately the video seems to the layman only show a "normal looking take off" but with a long (to their eyes) period of time until it lifts off, some sense of the plane lacking power to complete take off (unspecified), behaving erratically on the air (rolling) and then falling/bouncing/hitting/catching fire (any, all, or any combination of those in who-knows-what-order) to finally crash-n-burn a few hundred meters later.
But 3 or 4 cameras strategically situated on each strip of major airports would statistically be able to assist on investigations of many incidents during landing and take-off, no doubts. Someone should start demanding new large airports to deploy this.