Wood, the other point is, though -all GCSE syllabuses are being revised. Tweaks to many to remove continuous assessment has already hapend, English and Maths are new this year, all others will follow.
This will require a totally new set of textbooks for all subjects...and if the secondary reforms are anything like the primary ones, there will still be uncertainty about the curriculum in detail so much of the content will be 'best guess'.
Should all state schools buy all new textbooks for all new syllabs chanegs, even when they KNOW they won't be very good at the beginning, and then have to buy another lot a couple of years down the track?
Also, teaching from textbooks does exactly what this thread has a problem with - narrow teaching of a single route through a subject, with very, very limited scope for differentiation. Why should we of all people be advocating it?
Why do private schools do it? A smaller range of abilities, a much more old-fashioned and didactic style of information transfer, and an ability to pass the full cost onto parents every year, for starters.