I think we're seeing a lot of that. Some exceptions - NMB, Maiden every other tour - but largely, when you're selling 50,000 or 100,000 of your new record, tops, it's safe to say that most of the people in your concert audience are not there for that. I know for me, at my age now, many of the shows I go to are to show my kids what I grew up with; that in and of itself begs a sort of "greatest hits" approach.
I must be in the minority because I always want to see challenging setlists from my favorite bands. If I love them enough to pay for a ticket, I'm probably invested enough in knowing "all" the albums and therefore not wanting just the staples.
When I saw Dio at Wacken, I knew I was getting Heaven and Hell and Holy Diver. I was happiest when I got the surprises - Gates of Babylon and Stargazer. To this day, when I think of that concert, I don't think "yay, I finally heard Holy Diver live", but "Fuck yeah, I got Gates of Babylon!!"
Same with Metallica, yeah sure, it was cool there in the moment to finally see the fireworks exploding at the beginning and the end of Enter Sandman, but I remember the most them playing The Call of Ktulu and a shitload of Ride the Lightning songs, my favorite album. At my first Metallica gig they didn't play Nothing Else Matters and I didn't even care. They played it the second time I saw them, and I virtually have no memories of it. I've heard that song so many times that experiencing it live it was, dunno, like seeing Mona Lisa at the Louvre, I already know what it's like, seeing it finally in person it's just taking note that yes, that's the painting, guess what? it's how I already knew it was.