SANTA CLARA — Trent Williams isn’t being weird about retirement, so why should you? He knows the end is near, and, deep down, you know the end is near, too. The San Francisco 49ers certainly know it. We’re operating from a place of honesty these days. Let’s stop projecting insecurities or trying to re-write the rulebook. It’s professional football, not a magical fairy tale where everyone gets to play until they’re 65 and then collect a cushy pension.