This survey was publicized in all official channels including this week in rust, mentioned in the 1 year of rust announcement, on Hacker News (we cannot control traction), on the subreddit, the users forum, our Twitter account (where it also got huge traction) and literally all our other venues. We got a huge amount of replies.
Why was a link apparently not in the most obvious place, on the https://www.rust-lang.org/ web site? A small notice across the top would not have been disruptive, yet I and others would have seen it.
We put a great deal of effort into publicizing the survey, with a special focus on public spaces and piggybacking on highly-visible announcements. The website's front page sees less traffic than e.g. HN or the Rust subreddit, so it's not hard to imagine why nobody considered putting it there. It certainly wouldn't have hurt to have had it there, and I'm sure we'll consider putting it there for next year's survey, but we're quite happy with the several thousand respondents that we received.
I'm not sure how this is "poorly publicized".