The quote is particularly relevant when discussing space though. It's specifically the weight to data ratio that's called out as decadent. Something that's more relevant if you're used to travel with severe constraints on weight much more often than we are.

I agree that it's inevitable that things move that way - my only paper books in recent years have been to complete my collection of Ian Banks because that particular edition looks gorgeous, and Stålenhag's art books. I don't anticipate buying more paper copies of novels or textbooks unless there are books I can't find in digital version.

But at the same time, I just published a scifi novel and was surprised at how large a proportion of sales are still made up by paperback (not exactly selling millions, so it's not exactly a large sample of the market). It seems like it will take a long time before paper books become unusual to the point of being considered decadent.