Why demand research for computers but not textbooks?

Weren't one room schools just a bit of educational heaven? Corporal punishment. Easily intimidated poorly-paid teachers. Terminal educational level of 8th grade. Short terms interrupted by farm labor. Long walks to school, uphill both ways. Oh for the days...
In Evidence for Textbooks? Evidence for Classroom Computers?, Larry Cuban argues why textbooks don't need research to demonstrate their effectiveness, while computers do. In part, he argues that textbooks are just a historical staple of the classroom, and don't demand scrutiny:
Two hundred years ago, the most basic tools for teaching reading, math, writing geography, and history in mostly one-room public schoolhouses with students ranging in age from four to twenty-one were in very short supply. Before children had individual textbooks filled with the knowledge and skills they were expected to learn, the teacher had a book–the Bible, Webster’s Speller, or similar texts–and told students everything that was on the page that they had to learn. Initially before the Civil War, parents had to buy books for their children to attend school before some city schools (e.g., Boston, New York City) began to buy textbooks for all children attending school. From the 19th century until the mid-20th century, textbooks were the computers of the day giving students access to basic knowledge.
Textbooks were computers of the day? Larry, aren't computers the computers of the day today? Might a educational historian, even 20 years from now, write:
In the early 21st century the most basic tool for teaching reading, math, writing, geography, and history in public classrooms with students ranging in ability level from four to twenty-one was in very short supply. Before children had individual computers linked to the knowledge and skills they were expected to learn, the teacher had sets of dull, out-dated textbooks–and told students everything that they had to learn was in them. Initially, parents had to buy computers for their children to attend school before some schools and states began to buy computers for all children attending school. From the 21st century onward, computers were the textbooks of the day giving students access to basic knowledge.
If textbooks don't need effectiveness research, neither do computers. Let's just accept them as a basic modern tool (of at least the affluent) and evaluate not their presence, but their distribution and effective use.