FORTUNE — Google’s Android already has surpassed Apple’s AAPL iPhone in terms of market share. Now it wants to do the same thing in tablets, but is still facing very serious skepticism.

During a breakfast panel today at Fortune Brainstorm Tech in Aspen, Google GOOG executive Henrique De Castro tried making the case that Android’s open architecture will be the key differentiator that helps it topple iPad’s dominance.

“The reality is that the product is better when the ecosystem around it is better, and an open system is better than a closed system,” Del Castro said, while cradling a Nexus 7 device in his hands. “We believe it will be a huge benefit.”

But in a room where almost every attendee acknowledged owning an iPad, there was plenty of pushback.

“But that won’t make people buy it,” objected venture capitalist Alan Patricof. When Del Castro asked what Android would need, Patricof replied: “If it’s faster, easier, simpler or has more features… We’re all waiting for something better to come along.”

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