I disagree. There is a huge difference between OLAP and OLTP production - at least in our environment. In our hospital if the OLTP system goes down, patient care suffers as we move to paper methods of tracking blood, samples ... If our warehouse goes down, we may miss some trends, but the overall effect is way, way, wayless than the OLTP. And very, very rarily do our analysts use the warehouse outside of the 8-5 window. So if it goes down at night, no biggie. I would love to only have to worry about OLAP systems it would allow me to sleep many more nights.
Many would argue that they have critical OLAP systems that drives supply orders, bed boards, medication orders ... I would argue that, you don't have an OLAP system, but a ODS instead. And with our terrible hospital OLTP systems an ODS is usually a necessary item - but it should be managed as an OLTP system.