The bride at Japanese weddings is likely to wear both traditional and Western stuff. It's no wonder Japanese weddings cost around $300k. (Though I think they usually rent the kimonos and wear them mostly for pictures, because who has room to keep that in your apartment?)
Yeah, it all depends on the person. Just speaking anecdotally, from the five or so people I know of in Japan who got married in the last 4~5 years, only one of them wore a kimono as part of the ceremony. For all of the rest of them, they only did Western-style dresses. Changing dresses during the ceremony is indeed common.
And yeah, you can rent the kimonos, or it can be something that's part of your family (like in the case of the person that I know). Also—just as a bit of trivia—the sleeves on the kimono tell you the status of the person. Shorter sleeves are for the bride, or for those women who are married; longer sleeves (like in the photo above) are for women who are single.
As for pricing, they can definitely get around $300,000, but they can also be as "low" as $15K~$20K or so. The thing is, guests at weddings pay money toward the wedding—$300 per person is the standard in the circles that I've been in, but I'm not sure to what degree that could vary depending on person, area, or ceremony level. So, with that, the direct cost the couple/family pays isn't exactly the quoted price, since guests help with a decent chunk of that.