Or abandon the attempt at lecturing what's already in the book, and spend most of the time on Q&A (i.e. interaction, the stuff that actually benefits from having the teacher in the room). Bonus points: more people come to class having read the material, and people who already read it and don't have questions don't bother coming.
The few I've had that did this were amazingly useful - alternate derivations for people stuck on the book's approach, side explorations on things hinted at but not covered normally, etc. Many would get the homework out and puzzle through it in class too, and come up with Qs part way through. I wish we had this in other classes with a couple days between Qs and As, where you'd be left wondering what you actually understood if you weren't totally confident.
If your class is essentially a book-reading-but-verbal, maybe it shouldn't be a lecture / doesn't need the book? Some people learn better verbally, so a reading is definitely valuable, but not for all.
That can work with good students, but at most institutions, students don't do the reading and hence most learn nothing through this approach. It's the kind of thing that people who were good students tend to suggest because it would be ideal for them, but we have to think
about the other 80% of the class.
The course I'm currently teaching has, in addition to lectures, weekly two hour seminars where people are supposed to do homework/reading and then ask questions about it. (Not my design, that's just how it's timetabled.) But students don't do the homework or the reading. So, I seriously doubt that switching the whole course to this approach would work.
Yeah, it is a struggle for people who don't read before the class. Which is also why "nobody read it" tends to turn into "ok, so read it now" which does tend to bring up questions within about 10 minutes. But I've seen it convert a sizable number of people into readers, since it's an abnormality and takes a few classes to adjust to. Obviously YMMV though, it depends on everything, and nothing works for everyone in every situation.
Re last paragraph: I mean that I don't understand the point of spending a full lecture on exactly the same material as is in the book, unless the goal is almost exclusively to help people who don't learn well from reading, but do from listening. Which is a valid goal, but so far I've only seen an extreme minority claim this as their goal.
The few I've had that did this were amazingly useful - alternate derivations for people stuck on the book's approach, side explorations on things hinted at but not covered normally, etc. Many would get the homework out and puzzle through it in class too, and come up with Qs part way through. I wish we had this in other classes with a couple days between Qs and As, where you'd be left wondering what you actually understood if you weren't totally confident.
If your class is essentially a book-reading-but-verbal, maybe it shouldn't be a lecture / doesn't need the book? Some people learn better verbally, so a reading is definitely valuable, but not for all.