I'm thinking that once the people who grew up only with print media die, there'll be no reason to keep producing it. It's a generational thing. The print forms are kept around for the convenience of the non-digital generations. Once they're gone, there'll be no reason to continue wasting money producing physical versions of their products. We're only becoming more and more connected to the digital world. 30 years down the line, when this trend is further along its asymptotic curve, it's hard to imagine this future will contain the traditional forms of print media (unless it becomes cool/trendy/nostalgic, like LPs and record players).

It's old vs new and once the old die, the new becomes the standard. You can extrapolate this dynamic to other variants of social change as well (religiosity will decrease, tolerance will increase etc.).