An incentive? Let's think first about who will provide it. Who will pay for it? Who will organize it? The BTC foundation? Coinbase? Your family? All the users of this forum?
Exactly. So many threads about the same thing. Until somebody spends some casn nothing is going to ahppen.
You are both right that nobody in their right mind will spend his personal cash to advertise Bitcoin in a big manner. But we can all still do something. Start using it, not just holding. If you run a business then give a small discount for people paying in Bitcoin. If you run a Bitcoin company then you could do some advertisement for your business and this would also be a litte advertisement for Bitcoin.