There are at least 20 starter quality guards just waiting to be had at this very moment.
32 NFL teams
At least 450-500 starters and prospective O-lineman participating in NFL training camps across the nation
... and there just so happens to be 20 starting caliber Guards just sitting on their couch waiting on a phone call.
I believe these mythical guards that you speak of reside in "Imaginationland" peacefully coexisting with unicorns, Disney critters, and ManBearPig.