Can you elaborate why do you assume that such videos are likely to have a text equivalent?
You bring up lectures as example - I certainly don't have transcripts of lectures I've given, and neither do most professors/lecturers/whatever that I know; a few of them have most of their talk content in their slides but that's a horrible practice that distracts from effective lecture or presentation; in general all the non-audio material is intended to be a supplement to the talk and either are not meaningful without it (e.g. illustrations) or are not representative of the talk (e.g. a textbook chapter that's mostly about the same topic, but different). The recorded audio (if it'd be recorded) would literally be the only copy of the content of that lecture in existence.
The same applies for many other genres of video content. Most videos aren't scripted, and thus no script exists; heck, even videos that are clearly well prepared, staged and filmed with multiple takes (e.g. many of "youtube creators") generally don't have a script beforehand, the textual content is improvised on the spot and doesn't exist in written form unless it gets transcribed.
Interviews and podcasts are other good examples - as you say, many users who can hear would prefer to read it, I certainly would, but the obvious reality is that the textual version of those things does not exist unless it gets made, and making it takes much more time than recording the interview or podcast in the first place.
I was specifically referring to videos intended for conveying information, not entertainment. If professionally done, it has a script. If a college lecture, it has a corresponding textbook exposition. And you've seriously never written up any equivalent to any lecture content? It's all extemporaneous, all the time, and you can't spare the one time to write it down?
We don't have a tradition of teaching from a particular textbook (some universities do, some don't) so generally a lecture would include pointers towards chapters in multiple different textbooks, none of which match the contents of the lecture exactly (i.e. they're supplementary material, extra reading); and even if some lecture was based on a particular textbook, that text (unlike the lecture video/transcript) would be something that couldn't ever be published with a video because of copyright issues.
For my own teaching, no, I don't write up a "script" beforehand, I prepare content and plan for the topics and key points that I intend to cover in this lecture (and the next one, if we go quicker than expected), but the actual content heavily depends on how the students react, what they are (mis)understanding, what are the questions, etc. I don't consider well-scripted lectures a good thing, the lecturers that I know who are more into "reading off a script" give quite weak lectures IMHO.
Preparing in-depth textual material would seem a waste of effort as students would get the same content in the lecture. I wouldn't use it for other students since I'd anyway never give the same lecture twice - research is progressing fast, so my 2016 content is dated now and this year's content will definitely have to be rewritten (and the course restructured) next year. Admittedly, that's context-dependant - my situation is uncommon, there's a lot of teaching that involves lecturing the same introductory topic for many years off of a classic textbook to multiple larger audiences, and in that context your arguments would definitely apply.
But that's actually all offtopic.
The main issue is that none of this is equivalent to the transcript. Nothing of what you propose would make the video accessible to a deaf person. A textbook chapter or the lecture materials are alternatives to the video, it helps making do without the video, but doesn't make accessible the part of video where the lecturer is writing something interesting on the blackboard and explaining something that you can't hear.
I think you're the one who's demonstrating an atypical case here; most lectures aren't presenting on some rapidly changing topic, and even if they are, there is some Wikipedia text that is kept up to date.
>The main issue is that none of this is equivalent to the transcript. Nothing of what you propose would make the video accessible to a deaf person. A textbook chapter or the lecture materials are alternatives to the video, it helps making do without the video, but doesn't make accessible the part of video where the lecturer is writing something interesting on the blackboard and explaining something that you can't hear.
That's overstating it. The relevant metric is, if some deaf (or video-hating like me) person wants to learn the material, do they have a useful option? The fact that you can't make that specific video useful isn't relevant. Even pointing to some text that hits the same key points is major step up, and is trivial to do, and yet most refuse to do, just like most refuse to provide the one insight that they're making me watch a three minute video to hear.
You bring up lectures as example - I certainly don't have transcripts of lectures I've given, and neither do most professors/lecturers/whatever that I know; a few of them have most of their talk content in their slides but that's a horrible practice that distracts from effective lecture or presentation; in general all the non-audio material is intended to be a supplement to the talk and either are not meaningful without it (e.g. illustrations) or are not representative of the talk (e.g. a textbook chapter that's mostly about the same topic, but different). The recorded audio (if it'd be recorded) would literally be the only copy of the content of that lecture in existence.
The same applies for many other genres of video content. Most videos aren't scripted, and thus no script exists; heck, even videos that are clearly well prepared, staged and filmed with multiple takes (e.g. many of "youtube creators") generally don't have a script beforehand, the textual content is improvised on the spot and doesn't exist in written form unless it gets transcribed.
Interviews and podcasts are other good examples - as you say, many users who can hear would prefer to read it, I certainly would, but the obvious reality is that the textual version of those things does not exist unless it gets made, and making it takes much more time than recording the interview or podcast in the first place.