Scott D. Pierce: Nobody thought ‘Supernatural’ would run for 15 years. Nobody.

If, way back in 2005, you had asked me which of that fall’s 31 new TV series would still be around 15 years later, I would NOT have guessed that it would be “Supernatural.”To be fair, I wouldn’t have guessed that ANY of them would still be around in 2020. But “Supernatural”? A show about brothers Sam (Jared Padalecki) and Dean (Jensen Ackles), who traveled around the country in a 1967 Chevy Impala killing monsters? No way!And I’m not the only one. Both P