I cannot recall Zimbra saying they would be deflecting resources? Zimbra has also said that they would help their customers migrate to a supported platform if they are running the NE version.
I doubt Zimbra would put the FOSS version user infront of a paying NE customer. The FOSS edition is supported by the community and I believe the Zimbra staff help when they have available free time.
Remember, the FOSS community tend to upgrade before the NE users and help to iron out little buglets. I imagine this is why Zimbra offer their help to FOSS version users.
Think it through, everyone is helping each other. Its a community
