The Cardinals' Tony LaRussa will manage his 5,000th game tonight in Milwaukee. He is second to Connie Mack (7,755) in games coached/managed among the major American professional sports.
Even if the NFL does extend its seasons to 18 games, it would take the Eagles' Andy Reid until the year 2278 to reach 5,000 games coached. But that will never happen.
For one thing, he'd run out of timeouts by the late 2100s.