I think the issue you have is with capitalism. Artists don’t know with any level of certainty if their movie, music video etc will have any substantial return on their investment. So if you’re a studio sinking millions of dollars into something, you want to know that you’re gonna make at least some of that back, and negotiating ahead of time for a sponsored segment can help guarantee at least a small return. This is made much worse by the downturn of the movie industry in America with record low movie tickets being sold. It’s just becoming less and less feasible to make money from movies (and music/music videos for that matter but they’re a much different type of media) these days.

If people were able to make art for arts sake, not have to worry about people paying for it, being able to pay rent etc. then I think this would disappear almost entirely.