Ok time for some tough love my friend.
Well, social time is cool and things. But for me it is actually easy to make such social time. With this part I never had a slightest problem. But when I tried to move to next step - I almost always got some excuses on level of "I think of you as my best friend" etc. Actually this phrase is triggering me so much that if I hear it from a girl I just stop any communication with her.
The reason this happens is because you are not communicating
honestly. In other words, you are not moving the interaction forward sexually, which is the man's job (at least by default). Instead, you (and many other guys, sadly) are trying to BUY access to her vagina by investing TIME (6 months WTF??) and MONEY (presents, dates, onsens) and hoping to slip into a sexual relationship under these pretenses, like a Trojan horse of niceness. This is why girls hate "nice guys" (who actually have some pretty horrible beliefs if you think about it... that time and money mean a man is entitled to her vagina) and why the friendzone exists, because guys are taught to not risk offending the girl by making moves and being forward and instead hope that their time, money and being "nice" will be enough to turn her on (it won't be). That is unfortunately how both society and often women themselves say the dating process should take place, however it is NOT how it actually works. If a woman tells you this is how it's supposed to be done, don't believe her. They will always maximize the amount of stuff dudes buy them / perks of being a girl and minimize their amount of responsibility (which, to be fair, guys would do as well if they were in as high demand as girls).
Instead, you need to make your intentions known by communicating honestly. What this means is making a move on her if you find her attractive, talking to her as a man does to a woman, not as friends or language exchange buddies. Even if she turns cheek or rejects your move, she knows where you stand and will at least respect you for making the move and having balls, even if she's not interested. If she meets you again after you've made a move, she knows you will continue to do so and BAM you're out of the friend zone. You have to be willing to accept the fact she might not be into you, of course. In addition, respect her boundaries and it might take a couple dates, but it should never take six months of relaxed dating before you even attempt to move things towards sex. At that pace, she probably doesn't even think you find her attractive!
She needs to KNOW how you view her and that you are NOT after friendship. In other words, you are getting mad at her for "friend zoning" you but actually, it is you who friend zoned yourself so the only one you should be getting triggered at is yourself. Women are like mirrors and they reflect back at you the energy you bring into the relationship. If you don't like the way you're getting treated by many women, you need to change YOUR behavior, not rage at the women.
As for the onsen... be careful of dropping money on girls you haven't hooked up with. They certainly like it, but it doesn't "buy" you sex or anything like that, and they'll actually respect you less for it usually. Sad, but true. Re: noise from your room during sexytime... who cares?