I've reviewed the iOS Volume Purchase Program in some detail recently. It's not "enterprise" in any sense that I would use that word. To me, enterprise solutions means tightly coupled service and support, and negotiable terms/pricing. iOS VPP is a take it or leave it proposition.
I don't blame Apple for ignoring enterprise customers: they're usually a huge pain in the ass to deal with, and rarely have a clear idea of what they actually want. They engage suppliers just to have "a neck to choke" when things inevitably fall apart.
The iOS VPP is for purchasing apps that are most likely not made by Apple. How could they provide support or negotiate pricing for something made by someone else?
That's my point: it's not a traditional "enterprise" market. Neither price (what you pay to Apple) nor terms are negotiable. There is a certain amount of "support" involved, via the App Store approval/appeal process and transaction dispute handling, etc.
I don't blame Apple for ignoring enterprise customers: they're usually a huge pain in the ass to deal with, and rarely have a clear idea of what they actually want. They engage suppliers just to have "a neck to choke" when things inevitably fall apart.