Rationality and Decorating

Is there such a thing as human-friendly decorating which is gender non-specific?

I strongly suspect there is. The men's setup was specifically full of masculine-coded adornments (wood, leather), and the women's setup was full of slightly feminine-coded adornments (plants, lots of light).

But I think that there's considerable overlap, and there are also environments that are considered conducive to specific kinds of activities.

For example, most people seem to like dimly lit spaces for romantic activities or "night life" (though personally I hate dimly lit places; light is cheap, why should I struggle to see things?).

OTOH most people like to work in environments with lots of natural light, the "window office," because of the cumulative effect of sunlight on mood. (Being inside and away from the sun all day wears you down. I never noticed this when I was in school because I never spent long periods of time away from the sun. Now that I work in an office it's obvious.)

I think "jumped to a conclusion" is a bit strong; there are several possible explanations aside from "designers got it wrong until Thomas figured it out":

• The "Maze" structure was the most profitable when casinos were new, but it is now an overserved niche, while the market for spacious, beautiful gambling is (or was until recently) underserved.
• Women used not to gamble so much, but the successes of feminism mean that more women are able to do what they want with more money than before, so designing spaces that appeal primarily to women has become more profitable, and different designs appeal to women. (These first two points in conjunction would also explain why the masculine luxury setup didn't work - men were already well served by existing casino layouts.)
• Our cultural standards and expectations have changed, so the Maze used to be optimal always and everywhere, but now the spacious rooms are better at generating revenue.
• Building things like Thomas does used to be prohibitively expensive relative to the extra revenue it generates, but the cost relative to a "Maze" layout has declined.
• There is a new (relative to casinos) class of mass affluent, who don't go to super-exclusive places to gamble, or even the high stakes tables, but demand a more "luxurious" experience and don't like being trapped in a maze
• The maze was obviously a local maximum, and experimentation is expensive. Thomas may just have been lucky that his wild guess was right. The "men's club" luxury setup was an expensive wrong guess.

Is there such a thing as human-friendly decorating which is gender non-specific?

How about an intersection between male-friendly and female-friendly decorating (assuming that such things exist)? In your example, female-friendly decorating seems to be a subset of male-friendly decorating, so in this case, intersection equals to subset, so "having every surface covered with something expensive" is a solution which satisfies everyone.

Though I am a bit suspicious of the data. First, it seems to be somehow resistant to falsification, because even if I give you an example of something unexpensive which is pleasant to be around, you can replace it by an improved version of the same thing, which will probably also be a bit more expensive. In other words, are expensive things pleasant per se, or does it just mean that when you optimize too much, it tends to get costly? Second, decoration good for casino does not have to be good for other purposes.