I am just speculating, but I think the default Vector skin may be contributing to difficulty finding Talk and other items at the top of the page. Vector styling literally makes the editor-linkset fade into the background.
I would suggest you see if Monobook makes it easier to find Talk, Edit, and the other links for editors. I'm not sure if there's any recent data, but Monobook seems to get a lot of usage by editors. It would be painful to discover that the switch to Vector had diminished our inflow of people finding the Edit and Talk options.
Another thing, the user tests seem to involve only a single article edit. In real world use new editors typically make multiple edits before any Talk page activity. I expect more editing tend to help them finding the Talk page, and make them more familiar and comfortable when they do arrive at a Talk page to use it. The more edits they've made the more likely they are to recognize that Talk isn't really anything new, that it's just another page to edit. Alsee (talk) 07:04, 13 May 2019 (UTC)