I have not seen the documentary so can't comment on that. 

On finding new music, well, I don't have a method really. If I find something, it is mostly by accident. 

Spotify seems one of the main places people go now and I did sign up for it after you and the girlfriend of my friend's daughter mentioned it to me. I had an interesting time poking around there when I first signed up, looking at top tens from around the world, but then forgot about it until I just went back to it to use it for listening to Steely Dan and Donald Fagen albums, which are obsessing me of late. 

I kind of see the rock and pop genres now as being pretty much dominated by the existing songbook of music written between the 1950s and perhaps the year 2000. All of those songs create what would be a bunch of rock and pop standards that essentially now allow most of the artists that arrived after 2000 to cover, copy, remake, and use as the base for the work they do. 

I think artists now can just work from that rather massive and wonderful songbook in the same way jazz musicians have a book of standards. Plus as these artists die off, like Tom Petty is gone, it makes sense that today's musicians play those songs to keep that music alive. 

One night a while back I went to see Delbert McClinton and after the show chatted with his band. They play a lot of other people's songs but that is in that tradition of juke joint music and performing. They were a killer band and played all kinds of songs including Delbert's work. But when they let loose their sax player on a cover of Buddy Miles' awesome Them Changes, she was amazing. Letting that song live and breathe in a beautiful moment for an audience was a gift to all that were present. That's the only kind of place that will happen now, in some out of the way club where a group of musicians deliver that kind of experience. So, with rock music, or pop, I expect today's artists to break out those great songs. Go ahead and play them because the people that wrote them might no longer be with us or no longer be performing. 

I also think this is why cover bands have become so popular. You can see bands recreating the music of Led Zeppelin, Fleetwood Mac, Tom Petty, The Band, whatever, and for some it is nostalgic, for others it gives them a chance to hear and experience the power of those songs. 

I'm going with friends to the Eagles and Steely Dan show in Boston this September. I know you would love to be there, ha, and mostly it is to hear the songs of these bands played by what is left of their existing members. I never saw Steely Dan in their day, plus for a long time they did not tour, so seeing Donald Fagen and what I am sure will be a great band perform those songs, will be special for me. My friends are mostly interested in the Eagles, who now are down to Don, Joe, and Timothy that actually participated in making the records. That does not matter much at this point, they will play the songs and do them justice. Plus, Steely Dan once wrote a song that mocked the Eagles, which hopefully they play on the night I see them...just because it would be funny. 

This is the song and the line is "Turn up the Eagles the neighbors are listening." which comes in the section about "You were a roller skater..."

I think there is good reason that all these songs and artists have had such long lives, and mainly it is because all of that songbook was from the period where the music was birthed and continued to grow. 

Rick Beato does a lot of "Why this song is great." videos and chats. He talks to a lot of people that I ignored during their heyday, like Christopher Cross, to examine their music and what it meant and maybe, what it still means. 

Are their bands that will stick around now? I don't know. I mean in reality, The Beatles, Led Zeppelin, The Band, the Eagles...none of them were around really for more than a decade in their sort of record making line-ups. They continue to make an impression because they wrote songs that live on and on. Are their bands doing that now? I don't know but I think the way those songs entered the collective consciousness was different and the path to that was easier, through radio and album sales. Now we have this sort of pick and choose streaming option where the audience out there can all be listening to different things, not all tuning their radio dial to the Wolfman Jack radio show.