Something to consider is that what needs to be learned for a full and productive adult life does not really need to be begun quite so early in order to grow into fullness - a lot of it can come quite quickly and easily later on. Playing with those legos, and playing with other children, provides for a lot of practice of the imagination, and that in itself is a great foundation for all later learning.
We've all grown up with the work of the schools seeming to be so much more important than what children might naturally be more drawn to on their own that we've discounted the importance of what children are doing when having fun with things like legos and imaginative play. I certainly understand wanting to broaden the horizons - been there/done that, and learned the hard way. What I discovered was that my own notions about that whole thing tended to be shaded by school traditions that my child simply had no reason to relate to, and I think he smelled that - children see a lot more than we sometimes realize. He was learning plenty in his own way all along, and it really didn't matter one little bit whether he learned any of the things I thought were somehow important from those museum visits, field trips, etc.
I found that it helps for parents to just go ahead and explore the things they think are interesting, but not worry so much about leading their children into them - while fully supporting and taking interest in the things the children are interested in, but letting the children own those things, without parents trying to nudge those things into the realm of what the parent things is "educational." Natural modeling, good conversation and sincere enthusiasm go a long way toward facilitating a love of exploration and expansion of interests. When they feel that you really understand and support what they're doing, children tend to be a lot more mutually responsive to things you're interested in.
You mentioned that you've already been playing for almost eight years, but remember that most of those years were ones during which your child would not even have been in school - so it more realistic to think in terms of the fact that your child has actually been of traditional school age for a pretty short time and still has the drive to play a lot. Play is such an important experience, but it lasts for a pretty short part of life, whereas there's plenty of time in the years to come to get into the more academically relevant types of learning before any of it matters. A visit to a museum will expose a child to lots of things, but only a few of them might capture his attention at all - and the value of those things at that early age will not be the things themselves but simply the value that comes with the feeling of how fun it is to learn about new things. And if it's to the act of playing/working with legos and the act of connecting/playing with other children that a child is most drawn, that would indicate that those are the things that are filling the strongest natural drives he has right now.
As my child grew up to be a capable self-motivated learner, I got to also see children of friends and acquaintances grow up into fulfilling adult lives after having had plenty of time to indulge in such childhood drives - there's honestly no hurry to get into things that look more important to adults - it will all come with time and natural curiosity. Lillian