It's probably to do with click track control of lighting, stage FX, samples And countless other elements.
Click tracks arent just about timing for the musicians and it's not about drummers not being able to keep time.
Like many things, tech has made apparent big production value available to all. If you watch things like A year and a half in the life of Metallica, during One, there's literally a guy drumming on pads/buttons controlling the lights for the heavy section.
That kind of setup is expensive and was the territory of big stadium acts.
With automation, it's all triggered in exact time with the music, and not just lighting, but Pyrotechnics etc.
Festival appearances are big open air things, obviously. I can understand the criticism if it was a small venue or intimate gig, but festivals you have to stand out, and standing out, most of the time, means drawing attention to yourself over and above the music, and these guys appear to be headlining.