Nothing else you said really countered my point, which is what you are expecting a subset of a subset of a subset to look like the general population. You are expecting young game designers and artists from California to reflect the general population demographically, and on top of that you started with a number that was less than half the general population number.
To say that we would get from 7% to 10% by drilling three subsets deep strains credulity. Just looking at Gen Z alone can bring the numbers up to 15%. Millennials are not far behind them at around 10%. On top of that, you are filtering for creative people who live in California and are interested in nerd culture.