I think there is a difference between your desire to work your whole life in one job and actually offering stable employment. When you offer stable employment you do provide pathways for people who want to move from one job to another because they know it's going to be there, that it's not going to disappear. It's not being converted to something short-term. I think those two are quite compatible.
For individuals who want to have variety in their lives, as I certainly have in mine even though I'm not a millennial, you need to have career paths and opportunities internally to address that. It's not by creating temporary and insecure employment. In fact, I'd argue that temporary and insecure employment makes it much harder for millennials to plan their lives and to figure out what their career path is.