My guess is that if state-funded open source CC-BY textbooks are known to exist, substantial social and administrative pressure can be brought to bear on anyone

My guess is that if state-funded open source CC-BY textbooks are known to exist, substantial social and administrative pressure can be brought to bear on anyone who does not use them. Fine if you don't think it's good enough, but you'd better be able to justify it. Also, once they exist, if they're CC, then they can be updated to include whatever "innovations" come along in other texts.