There's probably an open source version of whatever you're trying to use, which you can unzip and deploy. Yet people don't do it most of the time, because they don't want to have to deal with it themselves and they value consistent experiences across industry. Gimp has been around for just short of 30 years and yet Photoshop continues to grow revenue every year. "Claude make me a Photoshop" ~= a very slow and expensive "brew install gimp" + "hey Claude just move some stuff around to make my gimp look different than everyone else for no reason."

Most people just don't want to deal with it. They want to focus on what they bring to the table and outsource the rest to people who specialize in, own, maintain and support that thing.