Yes, it does. It matters a lot. "The Word Gap ... has important consequences for children’s later vocabulary, literacy and school performance" [0]
Even if this whole line of research gets debunked, reading to your kids won't hurt!
> eventually converge to something approximating their parents' IQs
I haven't read much about this research, maybe it holds more water than I think. But does it matter? Do you really think disadvantaged youth are such because of genetics?
[0] https://www.sciencedirect.com/science/article/abs/pii/S08852...