It's absolutely insane to me how bad the user experience is with video nowadays, even video that's not encumbered by DRM or complex JavaScript clients.
The video experience for typical video files is great these days compared to the past. I think you may be viewing the past through rose colored glasses. For years it was a pain to deal with video because you had to navigate third party players (remember Real Player?), Flash plugins, and sketchy codec pack installs from adware infested download sites. If you were tech support for friends and family during that era, it was common to have to remove adware, spyware, and other unwanted programs after someone went down the rabbit home of trying to install software to watch some video they found.
The modern situation where your OS comes with software to play common files or you can install VLC and play anything is infinitely better than the past experience with local video.
I could hold shift and drag on the timeline to select, copy, then paste it into a document or another video. I can't do that with VLC today. Apple removed the feature in later releases too.
Today with modern tools like VLC or MPV and ffmpeg nearly anything can be viewed, streamed, or locally saved by your average user with basic Google search skills.
And the number of free and paid video editing tools as far beyond what we ever had in the past.
Then there’s the vast improvement in codecs. It’s quite insane that we can have a feature length - 4k video with 8 channel audio in a 3GiB file.
The only problem about the modern world is streaming companies who purposely degrade the experience for money. And the solution is simply to fly the pirate flag high.
But in the modern age viewing and editing a video are seen as two entirely separate tasks. You simply do not expect the video player that comes with the OS to cut, copy, and paste videos, even though cut, copy, and paste are basic OS-level features. This is very much different from the experience of almost all other kinds of files. You use Microsoft word to view and edit your word processing documents. Or if you aren’t fancy you use notepad to view and edit your plain text documents. These text documents easily allow cut, copy, and paste.
Some of the people who produce videos for a living require vastly different tools than someone who needs to trim the edges of a short home video clip, so the the UI and UX has to be different, otherwise these people won't be able to effectively do their job.
For writing, everyone pretty much does it the same way. You sit down, you enter characters with a keyboard, and sometimes to remove/edit stuff. Of course, there are professional tools for people who write stories for a living, that helps you keep track of arcs, characters, environments and so on, and many professionals do use them.
So while it looks like "Ah, Word actually works for everyone, why can't we do the same for video?" there are still professionals who need tools specifically for "writing stories" or "writing screenplays", and same in other areas :)
I think Word and other text documents are the exception not the rule. Image files have been pretty much always been viewed in different programs than the ones used for editing (although some viewers have rudimentary crop or rotate capabilities). Same with PDFs or PS files we alway view in something different than the editor. Nobody listen to audio files in e.g. Audacity.
In fact I can't even think about any other format except for docs where the editor is also the prime viewer (I suspect the reason is that originally consumption of docs was printing)