They were born of unique circumstances that no longer exist and are extremely unlikely to ever be recreated. The world has changed.
There's no secret formula or magic combination that will bring those things back. That said, I'm confident BYU football still has a lot of good days ahead (and inevitably some bad ones, as well). There's lots to look forward to as a fan, but looking backwards won't get you anywhere. And it probably wasn't quite as grand as you think it was, anyway.