It's not the launch of GPT, but probably about 4 or 4o that it really became solid. I also don't think video is there just yet, at least for video over 10 seconds.
You only notice plastic surgery when it's bad, but that doesn't mean all plastic surgery looks bad...
There's also the question of whether people are even trying to disguise AI content, and how effective that disguise is. Are you or I missing the AI-generated text that just has a veneer of disguise on it?
If you follow this thread up you will see the context is 'people who want to read content written by humans.'