I was the manager in a department of a game development studio for a major publisher in Europe, and now I run my own indie team. I've been working on gamedev for 15 years and have friends in many studios from all around the world.
Over 90% of the people who applies for gamedev jobs in Europe and North America and more or less fits the requirements (and those who didn't fit the requirements too) of these job positions in terms of skills and working experience are white males. The main reason is that to study gamedev is fairly expensive and requires a lot of time both in school and practicing or learning by yourself at home, and most people who can afford it in Europe and North America are white, in the same way that in the Chinese or Japanese studios most of them are Asian.
Many of these job positions are related to geeky stuff like engineering, careers traditionally populated by males. People are free to choose their career, and for whatever reason (biological, social, etc) some careers are populated by mostly only males or by mostly only females. But not only in the companies, also in the schools and universities. Nobody is forcing them to study or learn something, they choose whatever they want. The more free and the less sexist is their environment (when comparing countries in Europe), the bigger is that difference.
We always hired filtering by skills, talent and working experience. Not by tokenism (which is now being forced in many big gaming companies). We had a fairly diverse cast compared to the gaming industry average, but not because we were trying to hire diverse people. It was because for some job positions we didn't find people with certain skills/knowledge/working experience we needed and with the budget we had in our country, so we had to go to find them outside, and some of them turned out to be 'diverse'.
We hired the best candidates we found in terms of CV, being good doing their job, not depending on their genitals, skin color or sexual preferences. I think everybody should do that and get rid of the diversity quotas nonsense because they assume that there are enough good 'diverse' candidates when it isn't the case, in fact in most cases aren't even enough good white male candidates.
What stops people from studying that or working on that are personal preferences or being too poor to dedicate many years of that to study that in expensive schools and universities and to spend a ton of time at home learning by yourself. Universities or companies don't reject accepting people depending on their skin color, genitals or sexual preferences. If you want to increase diversity in these countries, make schools and universities and masters affordable to anyone, turn the majority of the population of your country to non-white, and convince little girls to become engineers in the future.
But well, having different skin color, genitals or sexual preferences don't make them work better or worse. If instead of focusing on choosing the candidates with the best CV you choose to fill a diversity quota you won't be choosing the best candidates, so your company/team performance will be worse.