Thats too bad. The art was one of the reasons why I like this series so much.
Artists usually withdraw because of the short deadlines and high workload. Some publishers solve this by giving the author 1 week break every 3 weeks, or stockpiling chapters so they are always ahead of schedule.
People dont realize how much time goes into making a HQ comic until they actually make one. I cant blame them for wanting to move away from comics
Companies are all about profit. If they can exploit someone, they will. There are countless stories of mangaka who get hospitalized or ruin their health because they have to meet deadlines (i.e. author of hunter x hunter). Some even die from over working themselves (i.e. author of solo leveling)
The comic industry is ruthless and competitive and some are desperate enough to work under these conditions for the chance to make it big
Well.. that's the thing, right? The artist likely voiced their complaints earlier and instead of changing their mindset and meeting the artist's needs, they decided they didn't want that artist, fired them, and replaced them. If one person will not do it for the given price and conditions, then it is not hard to find someone else who will. The industry is oversaturated so they don't need to bend backwards to please artists when it's easy to find replacements.
companies suck, and they don't care about the impact of these decisions unless a social media post goes viral lol

GUYS THE LINE ART ARTIST CHANGE AGHHH IM SO SAD I LIKE OG LINE ART ARTIST