Earlier quoted context omitted.
Mozilla CommonVoice is definitely trying. I always do a few validations and a few clips if I have a few minutes to spare, and I recommend everyone does. They need volunteers to validate and upload speech clips to create a dataset. https://commonvoice.mozilla.org/en
I wonder if they use movies and tv; recordings where the script is already available.
What might work better is using closed captions or subtitles, but I've also seen enough cases where those don't exactly match the actual speech either.