Maybe it's not a slam dunk, but it's something that should at least pass through your mind when making these decisions, and I don't think that's the case for a lot of people.

Does being able to deploy this argument in more situations suggest that it's a bad argument?

As for what happens if sharing X actually helps you in the future, you always have that option. Not sharing initially doesn't stop you from sharing later. Sharing initially does stop you from not-sharing later, if that makes sense.