I never read to DS1 until he was well over a year. I tried a couple of times but he wasn't interested - he didn't engage at all, just threw the book away if he got hold of it. But by the time he was 18mths or so I was reading to him a lot - it we went to the library, I could be there a good hour, reading books he bought to me. That was on top of reading every bedtime and several times during the day. He still loves reading.
DS2 was a bit different because he was listening from birth to me reading to DS1.
I agree with those who say that talking and singing are probably just as important, maybe more so and I definitely did a lot of that. I used to talk to my two non-stop and they both talked relatively early and read well now they are older.
I would like to know how 7 months has been chosen as the benchmark. It seems pretty arbitary to me.
That said, I don't think Bookstart should be axed but I do think it should be more focussed on those who need it, rather than a universal thing. I know, for example, that as a family we go to the library and own plenty of books and yet both my boys got the Bookstart packs and, unfortunately, we got duplicate copies of the same books. We could certainly have done without out it. The trick I suppose is knowing who can't.