Why doesn’t CO announce, on the plane before landing, connecting gate assignments near the conclusion of an originating flight? I think they used to (or am I thinking of UA?), and I know that AA still does this.

Yes, the FA announces that there will be an agent awaiting our arrival at the gate to answer all questions, and that one can go up to one of the many information boards for current gate assignments. But unless you are at the front of FC, a line tends to form around the arrival agent, or worse, someone is asking for more detailed information and taking up time. For tight connections, especially at EWR or IAH, having this information before hand can save precious minutes, and save on the stress level!!

Certainly not the most pressing passenger need, but something that I think would benefit us.