I can answer this. As a parent of two girls, I used to put a lot of pressure on them to boost their development. However, it took me a while to realize that they were just normal, gifted children who were experiencing too much stress, which was not helping their IQ. I stopped putting pressure on them and now simply love them for who they are. I try to support them as much as I can and avoid the mistake of pushing them too hard. I have explained to them that I want to give them tools to survive in this world, and that I will never be disappointed in them if they can't use these tools.
There's also indication that "nurture" doesn't matter beyond the basics. The foundation is laid from day zero, and it's just an archive extracting itself into what it is. As long as negative stuff doesn't harm that process, it's as good as it's gonna get.
I didn't lie to them. They are my world. As soon as I discovered the stress that pressure was causing them, I stopped pushing it. As far as I know, excessive stress decreases mental capabilities rather than improving them.
Why should I be disappointed in them? It's like being angry at the weather for not suiting you. There are only about 1% of people on Earth with an IQ higher than 145, and even fewer of them realize their potential. However, there are no statistics on how many of these individuals are happy. I would like to do everything possible to make my daughters happy, which is a much more challenging task. They do not need to participate in a rat-race to achieve happiness though.