Sometimes location and/or formatting is either bad or goes against "common convention". For example here on HN there is a mostly ok search build in. I had found it only after several years of using the site, and if I had to search for something before that, I've used google/ddg with "site:" option. Why? I guess because in 99% of all sites search is at the header, and footer contains zero useful information. I was trained that there is nothing there and so I've quite literally "didn't see" search box for a long time.