Youtube itself has a download button I thought. I haven't tried it since you have to be logged in to use it.

I remember that concert venues used to go absolutely berserk about people recording concerts, whether by video or audio. The Grateful Dead were a well known exception since they allowed audio recording, but they still prohibited video recording. There was a famous movie "Diva" about a guy who snuck a portable Nagra reel-to-reel audio tape recorder into opera performances to get bootleg recordings of a famous opera singer.

Today though, there are fancam vids of every concert uploaded to youtube immediately after the concert, or even livestreams during it. IDK what changed but I doubt it's damaging the concert industry. Ticketmaster on the other hand is destroying the industry.