This quote has made my day.
Frédéric de Villamil in his Docker review:
If I was still 25, the whole production would most certainly be full dockerized. At 36, I’m more reluctant to change everything for the latest hype. Not that I’ve became old and boring. But I’ve enough experience to think twice before giving myself the opportunity to work 24/7 during 3 days to fix what I’ve just broken.
Yes, that's why.