I think that's probably true. I try with my few friends who are in the middle, but I get intelligent responses from only one of the three.
It's probably most useful to think hard about what the friend is truly interested in, not what he or she is only somewhat interested in, let alone what we think they should be interested in.
Whatever we send should closely reflect that friend's deepest interests -- such as his/her livelihood, family members' safety, the community where he/she lives, or some extensive or unforgettable experience he/she has had. Most other things are likely to be unread, or, if read, to make no real impression.
Those are good points.