[See post 1 of the series for context.]
Argumentfor top-down, one-size-fits-all textbook adoption:
It would facilitate a smooth transition for students transferring between schools during the school year.
It would be irresponsible to advance this argument without numbers to support it. How many physics students in the San Juan Unified School District transfer between district high schools each year? Compare this to the number who do not transfer. Is it 1 of 10 physics students who transfer within the distrcit? One of 100, 1 of 1000? What exactly is the ratio?
Does a small service made to a few students balance favorably against a great disservice made to the many? Should thousands of students be subjected to a book their teacher dislikes so that the occasional transfer student has a smoother transition?
And how much smoother will that transition be? At the new school, he or she will face a different teacher with a different set of rules, different expectations, different procedures, and a different grading system. It is highly unlikely that the new teacher will be at the same point in the book as the old teacher was.
A coincidence of textbooks will be similar in value to a coincidence of lab tables: familiar, but so what?