You keep using "research" but it's not research when Gemini (or any other AI) responds to a prompt. Research actually requires time and effort - just like most things in the world.
For example, the "Adult Digital Content Market" information is directly ripped from this webpage:
You must be registered to see the links
Diving deeper into that page shows that, yes, it means much more than just adult video games, listing several types of areas. It's the entire adult digital industry, with videos taking in "over 70% of the user engagement" and video games being one of the other types mentioned.
Using the $6.98 billion that article sites - with a the bulk of that being videos and live cam shows, it's obvious that adult video gaming is not pulling in even $1 billion (in 2024).
Instead of taking what an AI says as being the answer - just like Wikipedia, it should only be the start of you, yourself, looking for the actual answer.
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But -- how much an industry is making doesn't tell a single developer what they should expect and strive for. That's like saying "look at how much hollywood brings in annually (about $40 billion or so in 2024)" - if you can make good quality low budget indie films, you can make a living. Uh, no, that's not the comparison.
Look at what others are making in the industry, individually. That's what my
research has done the past 3 years by taking Patreon data from Graphtreon and qualifying and quantifying the data:
As you can see in the data above, the median developer
who has paid subscribers (about 20-25% do not have any subscribers) on Patreon brings in about $100 USD per month... even after 4 or more years on that platform. That's after Patreon's percentage (8%-12%) but before credit card fees, transaction fees, and currency conversion fees (for developers outside of the US).
That's what people who are interested in developing an adult video game need to know: That it will be thousands of hours of painstaking work on a project with the likelihood of little monetary reward... unless they get lucky. Some of the best adult games with stand-out graphics and/or stories don't get a viable following to get a developer over the hump of earning a few bucks an hour.\
If a person lives somewhere that $1000 USD per month (before fees and income taxes) can give them a lifestyle they can afford while working on their project 80-160 hours per month, minimum - 5% of first year developers on Patreon make that cut and about 22% after 4 years do. If a person lives somewhere that needs much more (such as in the USA or a western European country) - then the chances are even more slim that a person won't be able to reap jack.
Or, a person can get a "regular" full-time job --- In the USA or western Europe --- starting at $13 USD per hour, 40 hours per week (which is shit wages, I admit) and bring in over $2000 per month before income taxes. They also know as long as they work 40 hours per week, they get paid. Plus other benefits a "regular" job provides.
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In the end, making an adult video game should be considered a hobby, a side-gig, --
a passion project -- that, if they get lucky, they might be able to support themselves at least as good as a "regular" job, if not a dream job.