I’m not confident it’s actually true that “phones have changed nothing”. They’ve certainly increased the variety of distractions one can access from a theater seat, as well as the ease of accessing them. But it’s also clear that most people have enough self-control to avoid using their phones for the duration of a musical, so it’s reasonable to blame those who don’t rather than blaming the technology. (This is distinct from the longer-term phenomenon of phone addiction, where there’s more room to blame the technology’s addictive qualities…)

This is the same argument that people use about "don't blame guns, it's people that are the problem"

Seems to me that theatres (and cinemas) should be putting passive farady cages to block signals coming in, I'd pay extra for that.