Certainly, as early as the 17th century and then during the Enlightenment, some of the authors hoped that reading their writings would stimulate thought and thus motivate an intensive social discourse. But many works make it clear that not every reading demands thinking, some publications, such as the Bible, merely demand faith. One should not think, but rather follow. Until today, many a scripture only allows time to evaporate and is at best meant to convey the gesture of attention.
However, Lichtenberg’s statement can also be doubted. Namely when the question arises what thinking is at all. After all, in any reading, the reader must imagine the images, sounds, smells, tastes, and feelings in order to be able to follow the internal logic of what is written, especially of a narrative. Thus, even with such reading, the brain has to work, although this should perhaps not be equated directly with thinking.
Postscript: Lichtenberg can be glad not to have experienced the development of modern media anymore. Since they do tend to require even less brain work.