Disclaimer:
For me,
#alttext is very much not about reach in numbers. It's about participation, fairness, and about sharing more than just an image with each other.
But I do like it very much that missing alttext is considered as such a massive no-no here that it does have a clear impact on reach.
So, if you want to have a heated or preachy discussion about why alttext is not (primarily) about reach: We agree. Feel free to constructively bark at a different tree. Thank you.