Oh, and trust me, I get that. But one big major thing about being an artist - the thing that gets you to the top in the first place - is being interactive with your community and giving people a reason to want to support you, whether it's because they like you as a person or want to see you succeed, or because they like your art and want to see it continue to grow.
If you're making half-a-million a year, frankly, from my viewpoint, your bills are covered just fine and there shouldn't be an excuse anymore to continuously ignore anyone who doesn't contribute, because you're already basically set for life at that point. I know that you do have to keep giving stuff to people who support, but that doesn't mean completely shut out those who don't, especially because some of them might be supporting you in other ways - like sharing your art with people who haven't seen it yet, following your updates and commenting/liking/etc. every day, and basically just being a good part of the community. I dunno, maybe I just need more of a reason than the art to support someone? But I can't be the only one.
I mean, she can afford to have contests where she gives away up to $3000-$5000, probably more. I'm pretty sure she has no trouble paying the bills at this point, so the only part left is getting to -keep- people on her side, and that's not gonna happen if she's not well-liked. Some people will do it just for the art, but others, not so much.
In terms of your analogy between plumbers/pizza guys/Sakimi-chan, let's raise you this scenario. You order pizzas from this pizza place, but it seems like every person who brings it to you is a total dick. The guy on the phone is a dick, the guy who drives the car is a dick, and even the mascot on the website is a dick (okay so now I'm being a little silly here lol but bear with me). In the end, unless that pizza is the creation of God and you're willing to stick with it just for the product itself (which, albeit some people will do, if they're dedicated to the food/product), you're probably gonna get real sick of that pizza delivery place's shit. If you're not gonna get good customer service, you're gonna find yourself feeling pretty pissed off yourself and chances are, you might not go there any more and take your money elsewhere.
Artists are no different. When it comes to the business side of art, you do have to look at the money, but you can't forget about the social side of it either. I see artists all the time who make a decent amount a month from Patreon/here/etc. but still take the time to do livestreams for everyone, offer contests for everyone, etc. whether they're paying or not, just to help give the non-supporters a -reason- to support. People don't have to pay for the roof over her head, and are only paying for the benefits; and if they see past that illusion and realize they don't like the person they're supporting, then the artist themselves is gonna be in deep shit.
As for the art itself, the only thing really special about it is the cartoon character representations and the gender bender art. In terms of style, as someone has pointed out already, it's actually quite common and quite a few people have mastered it, making the style itself somewhat obsolete. I'm not saying it's not GOOD. I think it's great. But I also think the same of the many other art styles out there on the front page of DA that are -exactly- the same, some that even came BEFORE Sakimi-Chan.
So to make things short and clear, it's not that I don't like Sakimi-chan's art and her business. I think she's doing a wonderful job - and she must be to make that kind of cash every month - and hell, I used to be a supporter for her. But the amounts for rewards are going up, the highest bidder is getting all the attention as "the one that's making a difference" and everyone else, including the non-supporters who helped build her original fanbase, are left to sit in the dust, and unless you grew up as her childhood buddy, she's not going to bat an eye if you throw anything into the pot.
But maybe this is all stemming from the fact that this social downside of it is what I don't want to become. I'd love to be making 23k a month from my art alone, but I never want to forget the people who would have helped get me there in the first place. I just don't want to be one of those artists that becomes too busy and too good for the community they started in. There are so many artists I admire, but I wouldn't want to be them because I feel like I'd be miserable not taking part in the community; it's such a big part of what I do, and what many others do as well.
So again, she's doing great in the business of it. And hell, she could be donating half of that pool of money to charity, I don't know what she does with the rest. But from what I've seen, she could be doing better in the social part of it to help keep that business part of it afloat. That's all I'm saying on this.