Lmfao. Having recently graduated from a Game design school, let me tell you that making a game accessible isn't nearly as complicated as you seem to think.
It's mainly baout making games more customisable.
Difficulty level, the option to change input, different colour filters to cater to vision impairment, etc.
Adapting games to the most disabled/impaired also helps to accommodate the less disabled and everyday joe.
Having customisable input helps people who are left-handed enjoy games for example.
Having the option to have more contrast can help people who are playing in the sun by making the screen more comprehensible.
The part of game development that takes the longest is the game development in itself.
Designing the game, making sure everything makes sense, establishing the artistic direction, producing the assets, optimising everything, game testing, etc.
Excluding a whole part of the population for a minuscule part of the game development process is just ridiculous.