Though winning an Oscar, in any category, is seen as the height of accomplishment within the movie industry, it doesn't ensure those who do win the prestigious award are automatically immune to the challenges of filmmaking.
It just means they did everything brilliantly that one time, but their next film, or the one after that, or any number of projects they'll undertake in the future, could be a completely different story altogether.
And history has shown us that this can oftenbe the case.
Yes, it's unlikely that a director (even one of the greats) will have a perfect run from the start of their career right to the very end, but some of the trash churned out by people who've won an Academy Award - an indication that they've refined their skills and are capable of crafting nigh-on flawless movies - is often hard to believe.
Men like Ang Lee, Ron Howard, Oliver Stone and Steven Spielberg have all succumbed to this post-Oscar mediocrity display, and they're not the only ones who rose to the highest of highs, only to fall back to Earth with a spectacular crash...