In general, I believe there is too much dependence on text books only for teaching a class.
Even if text books are out of date, teachers should be up to date enough with current affairs to fill in the gaps. That's what my teachers did.
The text book should be the skeleton of the course. It's up to the teacher to put flesh on the bones.
There is too much teaching to the test these days.
There are also too many teachers who seem to be only one chapter ahead of the students.
I've seen teachers mispronounce words from spelling/vocabulary lists, not be able to answer history questions from the students, and give wrong answers to science questions. They spend more time on the techniques of teaching, and administration of the class than anything else.
The kids don't seem to read much of the text books other than search for the answers to the chapter questions, so the impact of the Texas decisions probably won't be that great.