This reminded me of this article I read a few years back. I wonder if they still use the same method.
https://netflixtechblog.com/ava-the-art-and-science-of-image...
https://netflixtechblog.com/artwork-personalization-c589f074...
https://www.theguardian.com/media/2018/oct/20/netflix-film-b...
1: https://hard-drive.net/wp-content/uploads/2021/05/youtubers-...
Almost all of them, surely. Maybe not consciously... but unconsciously certainly.
Films are incredibly expensive products to produce, an average of $100 million dollars apparently [1]. Do the incentives really not align to pay for professional artists to create a high quality thumbnail? I doubt it. Hell, youtubers have figured out it's worth doing this on every video which cost and pull in 4-5 orders of magnitude less money.
[1] https://www.investopedia.com/financial-edge/0611/why-movies-...