How the history of early 21st century of music will be documented

I noted a few months ago to someone that the history of early twenty first century music will likely be documented for the most part in shaky video taken on mobile phone / digital cameras.

This theory seems to be borne out by today's experience. I went to upload footage of a new Gemma Hayes song (Oliver) to YouTube, only to find that two other people had already done so - from the same show. Now, keeping in mind that this was a show that had a capacity of 300 and wasn't full - let's say 200, and I know that my friend also filmed it given that he posted it on his blog, can we assume that 2% of the audience at a gig are filming any given song?