Here you have (albeit small) proof of some sort of trend: https://trends.google.com/explore?q=codeberg%2Cforgejo%2Cgit...

Still, doesn't come close to popularity of GitHub itself today (https://trends.google.com/explore?q=codeberg%2Cforgejo%2Cgit...), but I think the trend of moving away from GitHub is clear both in data and sentiment, both qualitative and quantitative.

The existence and growth of the codeberg project does, however.

Stackoverflow usage didn't fall overnight either. But it has gone the way of MySpace and Oracle.