I am also trying to figure out what happened to the missing preview movies in the Text Presets folders. It is appalling that Adobe has not fixed this yet. To make matters worse, last night I updated to the new Bridge (22.214.171.1248), and this is STILL broken. I had hoped they would finally restore this area, because several months ago, I spent an hour on the phone with tech-support, explaining in detail how they forgot (?) to include the sample movies. He was unaware of it and said he was going to report it as an urgent problem to fix. I never heard back on that one.
For years, Bridge had small movies that showed how the text presets animated. I think they were still working in 2017. Then the movies suddenly disappeared, and were replaced with small pictures, which are fairly useless. Plus, many of these pictures are missing, which really makes it look like a botched mess. It's like some programmer forgot to copy the movie files over to an update, and now this mistake is stuck in the system.
It is mind boggling how they could be so sloppy with their software. There must be an easy way for them to fix this. Why can't they find the original files and put them in the right folder so the sample movies play again? Why do they continue to overlook this broken chunk of Bridge? Are they such a huge bureaucracy that these messages are not getting through?