Why is marriage so uncommon in gaming?

Haru is a girl...
Yes, Haru is, but what about Arisu?

i actually want to marry Sakuya, i like well done big meaty girls

Because it's typically a logistical end point. You get the girl, fall in love, date, and eventually get married. Beyond that, there's no further goals on the romantic side of pursuing the relationship. Wedded bliss is about constancy, maintenance, and keeping the spark, which really doesn't make for an interesting story. Introducing conflict when we're already in the wedded bliss stage is really just going back to retread will they won't they territory, except now it's about whether they'll be able to keep things together, which is less of a happy potential and more of a concerning one. Unfortunately, this means the dichotomy of a married story is basically that either the married status is ultimately inconsequential like Skyrim or is in pursuit of the logical next step of children like Conception or Agarest War.

Isn't idolmasters just some cuck game where you prepare bitches to get fucked in the idol master, becoming masturbation material for the nation? Why are people pretending there is romance there?

Tachibana-san.

Isn't conception where children get made in the lab without even any sex?

Because most of the idols end up loving Producer and every summer a few literally get wedding dresses

Not sure. I was told years back when it was being discussed that there was this focus on marrying a partner from your team to generate a powerful child for the next gen, but I may be misremembering.

What has summer to do with wedding dresses?

June is considered a lucky month for weddings in Japan, or so I've been told. Something about long wedded bliss and such. I got married in June myself, but I didn't know about that until years later.

I asked more in the context of the game because you were overly specific with the season. I thought it was some kind of event period in the games.

You like Haru now

how many weddings have you heard of taking place in the middle of winter?
everyone (women) want to get married on a nice, warm day where they can have a big outside wedding.

Can't argue with that. The ceremony at mine was in this cool old bank vault, but the reception was on a rooftop overlooking the river. Some friends of mine got hitched in late October, and it was frigid by the time the ceremony was done, so the reception stayed inside.

The wedding I remember most fondly was in winter. Inside it was lively and if you had enough you could go outside with someone for a walk, it was very comfy and silent outside which served as a nice contrast. Though this was more than a decade ago and snow is not guaranteed nowadays in winter and snow gives all the magic so if it isn't there it would probably suck.