I'm always hearing stories reciting gig fees readily available in the 70's, 80's, etc. I know, I earned my living in those times. It's true, gig fees haven't kept pace with inflation, that's for sure, but hang on just a minute, there's a bigger picture than just venue cost cutting and/or exploitation. The author is excluding the greatly diminished value of live performance. Back in the day, people didn't have anything like the availability of instant entertainment they have today. If you wanted to listen to a song, you went out & bought the record. Either that, or you recorded it from one of your mates. Videos of live concerts were few & far between, & you were pretty much limited to watching whatever the 3 or so TV channels decided was worthy of air time. The live concert was a big deal. Live music was a big deal. It sounded so much better than recordings of the day. It was a total experience, both audibly & visually, & then there's the sense of occasion.
Of course, these days, you can get hold of pretty much anything you want. The audio & video quality is in a different league to that of a few decades ago, & most content is free, or close to it.
What I'm getting to is this. You used to be able to set up your kit, a few amps, maybe a light or two, & jam out a gig. Now, people expect more, much more. The game has moved on. We're competing with crisp audio, clear video, fully mobile music access, so setting up in a corner & delivering a budget sound just doesn't cut it anymore. People want & expect a total experience, & those who deliver that get the best piece of the pie.