::: spoiler Transcription A Bluesky post from "Slippy", @damnslippy.slippy.me, with a profile picture of a woman with short, purple hair holding a knife: Sincerely delighted to discover, 45 minutes into this nearly-wordless three-hour documentary about French monks who take vows of silence, that among the reasons they \*can\* talk is "to make sure the monastery cats know when it's mealtime by making little kitty-calling noises at them." :::
Personally I often use the body to add a transcription (not to different from what I put in my comment above), rather than use true "alt text". The main reason is that I often want to write more than the amount that feels appropriate for an alt text (including having paragraphs), but the visibility of it is an added advantage.
It honestly shouldn't be that hard. Just use both alt and title text properties, the latter of which shows up on hover, and on mobile at the top of the OS's default long press menu.
But I do agree that the tools should be made to assist. Mastodon basically yells at users to add alt text. Pixelfed already does my suggestion of mirroring the alt text to the title text.