Take a look at Veritasium's perspective on this issue [1]. Veritasium reflects on clickbait thumbnails from the content producer perspective, and balances that against the motivation behind YouTube's algorithms. His final conclusion is that cilckbait isn't all bad, and that it serves an important purpose for both viewers and content creators. His classification of clickbait into different types is also fascinating.
Very minor anecdata I would like to share: I have discovered Veritasium like most others, at the time when they weren't "clickbaiting", when their videos actually had the thing that they discussed right there in the title. I learned tons of things. Each new video, and each title, made me eager to discover that thing.
But around the time they implemented their "clickbait" titles and thumbnails, it had the opposite effect on me. They all just *seemed* like so many other videos: bland and tasteless. The content itself hasn't much changed, but the allure certain has diminished for me. I've stopped watching their videos.
Compare that to Curious Droid, or Practical Engineering, which still use descriptive titles, sometimes questions, but always exactly about the subject.
[1] https://www.youtube.com/watch?v=S2xHZPH5Sng