There are tons of ways to encourage your child's academic abilities, not just tutoring or extra work at home. I think a child who is properly listened to, not just yes dear what a great idea, but actual engagement/responsiveness with or to whatever they are talking about will probably have a good shot at being academically successful if the raw material is there (which might be partly genetic but not all) - the skills for academic success are pretty much the same as those used in conversation, explaining something, putting forward an idea, working out how to say what you really mean (and maybe what you actually do mean), perhaps coming up with your own answers to a question etc.
There was a study about gaps in attainment at preschool level showing that some children had heard thousands and thousands more words than others, and guess which were doing better?
Yes, we all know that time when you just cannot be arsed to think any more about how great sky cars would be, but saying 'wow, that's such a brilliant idea' is qualitatively different for the child than saying 'wow, how could that work? How would we stop them crashing into each other? How would you know where was safe to drive? Would there be another kind of road in the sky? What would you need to be able to do to pass a sky driving test?' etc. Both are nice ways to respond and will be positive for the child, but one gets the child's brain working and the other doesn't.
Also, starting early probably makes a difference IMO. I do not, by the way, mean pushing little children to read or write or do maths before they are ready! I mean genuinely encouraging them to think around a question and work out what the answer is in their own terms as much as possible. This is probably an enjoyable activity for anyone who is going to have the potential to be academically successful.
Why can't cats talk?
What do you think is different about a human and a cat? What do you think talking is useful for? Are there times when a cat would need to be able to talk? What do you think cats would say if they could talk?
is v different from
Why can't cats talk?
Only humans can talk. Humans are cleverer than cats. Humans are built differently from cats. Cats don't need to be able to talk.
I think that's where the academic attainment of mothers comes in and it must make a massive difference if you're being treated as someone who can work things out for themselves vs someone who needs to be told stuff, on all kinds of levels.