I also think some children fall into traditional gender roles because they are people pleasers. In fact, I think that is true of both of mine, but it means their social behaviour is vastly different because they both want to fit in with the group.
Dd works incredibly hard to present an image of a mature, responsible, hard working and caring person, because that is what her peer group likes to see and she is afraid to lose friends if she appears different.
Ds in the meantime finds he can be popular by not taking school (or anything else) seriously, but just mucking around.
Same motivation, different results.
"Graphics is usually 85% boys, and textiles is usually 100% girls. Same teacher, same kids, same expectations."
How do you mean same expectations? Do the peer groups of those boys have the same expectations on them to do textiles? Surely not? Or do you think peer group expectations do not matter?
When I was at secondary we had a choice between textiles and woodwork. I was pretty bad at both but possibly marginally better at woodwork. So I chose textiles, because I felt if I chose woodwork I would need to be good at it to justify my decision; otherwise, people would be asking why I'd chosen it and make fun of me. Textiles were the default position so left me nothing to prove. The only girls who ever chose woodwork were the ones who were exceptionally good at it so had the confidence to make an unusual decision. Iirc no boys chose textiles.