There's certainly more respect (and legal backing) for privacy in Japan, which makes things like producing uncommon, off-color, or even transgressive art less risky. People can't just take pictures of you in public and post them online. You're not expected to become an artistic personality, either. Your art (and perhaps a pseudonymous personality) can stand on its own, even when you make public appearances at physical markets, without any of it leaking out into your non-subculture life.

You're also not expected to turn the effort into a massive commercial effort. Some doujinshi are only produced in tiny runs that are meant to be distributed to friends, and maybe a handful of interested customers. That means that the production standards are more forgiving, the investment is smaller, and the barriers to trying again if a particular effort doesn't go so well are lower.

It's more common to know someone's name if they break out into more mainstream music, such as Kenshi Yonezu (he's done music for Ghibli, My Hero Academia and Square Enix...but some of his most famous work is under the name Hachi). There have been many others who have had that trajectory. Ayase (half of YOASOBI), Reol, Giga and Ryo (Supercell) come to mind.

I think there's also just more of a societal emphasis on craftsmanship and honing skill as its own end. The US has been smoking the capitalist crack pipe for so long everything is either about consuming or producing something of value for others to consume.

In Japan there is a presumed collective endeavor to creativity. That starts in school and continues into the professional world: mangaka will plagiarize from each other in the pursuit of a collective storytelling lamguage (a concept introduced to me by Even A Monkey Can Draw Manga, a great humorous short read on simple realities of the industry with practical advice). Someone who makes a bad drawing is given a lot of leeway to be "pulled back in line", for better or or worse. The professionals complain that everyone copies from everyone else overly much, and the pressure at the top level to continuously put out high level work is deadly intense, but it creates the high standard of uniformity.

But the US culture guarantees a lot of awkward standoffish scenarios because, if you make art, it's positioned relative to the worst framing of your ambition, and this typically means you are viewed as a speculator, someone who is plotting a way to cash in without doing something for others. It's far more acceptable to say that you are an art teacher than an artist because then it locates you within the structure of the firm and the state, which is the "hidden" collective tendency in US culture: be as individual as you want if it builds the nation in balance sheet terms, otherwise you are a failure. Thus the observation from earlier in the thread that a sports fan is more deserving of respect than an amateur athlete - the fan is a consumer, they are participating in the market.