I sure think so

More specifically, I think it's totally possible to steal an art style, but it happens very rarely and similarities between styles doesn't equate to stealing. I've seen the more distinctive styles developed by very famous artists copied to a degree where I would have difficulty telling two of their pieces apart. This isn't to say that popular artists have a monopoly over a style and can attack those who use aspects of it as inspiration in the development of their own, but when it is clear that every aspect of their style has been replicated (usually in cases of what I would personally classify as actual style theft, the artist began by tracing the art of the owner of the style, and over the course of a long period of time they begin to be able to freehand art in said style), that may be cause for intervention and a civil discussion.

My thoughts on this topic are very complicated, but I tend to get frustrated when people follow behind the idea that the concept of art style theft is impossible just because some relatively influential YouTubers made videos addressing this subject and came to that conclusion. I don't really mind those videos so much; their opinions are their own and I'm not here to argue against people disagreeing with me.

I used to be on the 'there's too many variables involved in creation of an art style to ever be truly copied' boat too, so here are the things that changed my mind:

Look up any "20 style drawing challenge" on YouTube and you'll see that styles can be replicated with relative ease. It may not be identical for some younger users, but more experienced artists who partook in the challenge were able to draw their characters (in a different pose than the reference image and w/o tracing) in whatever style they chose to a very impressive degree of accuracy. I remember specifically a few Attack on Titan ones that looked right out of the anime.I encountered a user who'd been involved in some drama for who replicating the style of a very popular artist over the course of about a year (give or take). Both the popular artist (nicknaming them PopArt) and the young artist (YA) won't be named just in case. PopArt was huge at the time for their fandom-related content, and their style was fairly unique in that they drew primarily humans in an era of the internet where cute neon cats were all the rage as well as having a very distinctive method of doing their anatomy/coloring/lineart/characters. A lot of people had utilized aspects of their style (and still continue to, if they can find art pieces that hadn't been deleted in a fit of drama-fueled rage), but this went above and beyond. Most of the art in YA's gallery was directly reminiscent (i.e. the concepts of the drawing as well as the style were duplicated; they would draw a character with a TV/screen-based object for a head that looked like a rebel, do a meet the artist with the same pose, create a themed online "family" composed of the same number of basic members and overlaying googled images of galaxies over top of every drawing of them) of PopArt's works, and it seemed that whenever PopArt did something major, they would follow in suit. If they were drawing themselves and their significant other hugging in the void, YA was doing the same. If they were doing a meet the artist meme and skipping certain panels, so was YA). From an outsiders' perspective, it was a bit creepy, but it didn't surpass anything besides dedicated fan who wishes desperately to be PopArt by trying to emulate them to the most minute detail. It came off as extreme insecurity, and although they did get into trouble with PopArt's fans telling YA to stop "copying" whatever PopArt was doing and their style developed into something more original, there are definite and prominent traces of PopArt's style left in their work.

(Just for further clarification, the style in question isn't just a few special ways that they draw eyes or proportions. The heads are rectangular and many of the body parts are cubical while specific other parts remain rounded. The hair is both spiked and rounded, the lines are done using a certain tool in paint tool sai set to specific settings. I'm not trying to say that the art style is the most original thing in the world and that nobody can ever do anything similar, I'm just trying to explain how obvious adapting certain aspects of this style would be in others' work, let alone utilizing the whole nine yards as your own)

This sort of situation is rare, but it's one of the few that makes art style theft a real thing for me. I don't really care too much about the whole concept, as it doesn't seem like that big a deal especially when an artist is going to evolve on their own regardless of how much they try to copy the ways of another, but when people write off situations where it's clear that more that entire styles have been meticulously learned and replicated just because a YouTuber told them that it's not possible.

A lot of popular art styles are very generic (mine included!), so actually picking out what's theft and what's not is difficult when everything blurs together. As a rule of thumb, though, I'd just assume innocence unless it's bordering on creepy.

Reiterating this because it's the internet: this is my opinion, and since my communication capabilities are limited due to the fact that I'm writing this down and not articulating it out loud with clarifications and inflection, it's likely going to look overly complicated and nonsensical at times. Feel free to ask questions if you want.

What are your thoughts? I'm curious as to everybody's opinions on this, since the internet seems pretty split.