Anchoring fails because let's say the position is wanting to hire someone at $70k and you state an expected salary of $75 - 80k, negotiable. That employer may decide it's not worth their time because you'll want too much, so why bother with even calling you in for an interview. Asking for a salary number from applicants up front is not just a way to undercut them, but it's a way to quickly weed out and only interview those who are willing to take bottom dollar.