If you give them a
choice, the book companies won't do it, which makes commercial sense from their perspective. It's explictly supporting a form of exclusion for disabled people. Also, you seem to be under a misunderstanding. If you're legally blind in the UK, if you
legally own a work then you're entitled, without the publishers permission, to aquire a large print version. It's not a free for all, it's an accessability provision.
More... There's no
need for the publishers to have to pay the costs of providing, say, a red tinted background book. These things can and are done by specalist companies and volunteers for disabled people.
In the case of the Kindle, assuming they add voice navigation, I'd be fully in favour of a provision in the software for legally blind people to be able to register and to have, via whispernet, the TTS settings for their books turned on regardless of the publisher's settings. (This is not the same as audiobook versions...)
tldr version;
I support
Right to Read.