He talks about the youtube algorithm being the primary driver for the shitty thumbnails https://www.youtube.com/watch?v=DzRGBAUz5mA vs his traditional one that got buried.

Not sure about his other stuff you claim, I'm not a super big video guy for tech things (just let me skip and search ahead easily) but this came up with my friends a few years ago after people started noticing many videos from various creators going to this format of thumbnail.