It depends what you consider to be a "slight bump under the hood". Desktop computers have matured to the point where every iteration is a "slight bump under the hood" yet people continue buying them. I think the iPhone 5 is going to gain more from iOS 5 than from new hardware. Mobile requires a balance of power and efficiency. I think the hardware is going to be enough of a bump to support the amazing features of iOS 5 and nothing more. iOS is what is going to sell this...
Although you already got one answer, here is another way to look at it. If this were not the case, there would be no protection for IP at all. Suppose that company A wanted to use company B's IP without having to pay for it. All they would have to do would be to set up shell company C to steal the IP, and then use C's infringing product without any liability.
Is Lion struggling in enterprises? I haven't seen anything about that.
As for the app store, I thought there were special ways for businesses to buy group licenses. And since Microsoft is moving the same direction with Windows 8 and their app store, I can't see how Apple would be put at a disadvantage. Why not take the burden of application updates off of IT and let the app store manage it?