25k in comments is a lot of words (a full time writing job), especially as that is on top of reading & comprehending the posts.
My own writing output is aimed at 5-10k words per week.
The time to add 2+ times that as comments for many folks (def me) is not available.
But, that consistency of posting and interacting combined with quality for both is as essential as you say.
You are right it is a lot and it all adds up. But when involved with some decent content, it is easy to do. This is especially true when answering people.
Conversations are important and getting them going is healthy for the individuals involved and the ecosystem.
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