Here's a thought experiment.
Satoshi Nakamoto should offer a million bitcoin reward for the first country (or group of countries) to completely abandon its national currency and make Bitcoin the exclusive legal tender for all debts public and private.* The reward could be paid to the government of the country over a 20-year period, just to make sure they don't start down the path, collect the reward, then go back to issuing their own currency.
Imagine a country like Argentina after the next round of hyperinflation.
1.* In anticipation of this move, the government might secretly spend a few million dollars to accumulate a few tens of thousands of bitcoins while they are still cheap.* If they have USD or other currencies in reserve, they could secretly convert those to bitcoins, as well.
2.* When their current peso gets in trouble, instead of replacing it with yet again another new one, they could simply declare Bitcoin to be their national currency.
3.* The price of Bitcoin should jump at least to at least $100,000 at the news, so their first reward installment of 50,000 XBT should be worth at least $5 billion.* This would allow the government to significantly increase its expenditures and/or lower its taxes.
4.* They modify their tax code as necessary, since it's hard to track income and sales, so it makes more sense to tax by user fees, per person, or based on the value of property.
Their economy should absolutely boom because of the advantages of Bitcoin, plus the $100 billion prize, plus the enormous appreciation of any bitcoins they accumulated before the price jump.* The government looks like a hero and probably stays in power, at least until the reward payments stop.
It doesn't have to be Argentina.* It could be any country whose currency gets into trouble, or a bloc of nations wanting the advantages of a common currency, or maybe even the U.S.
The first nation to make the conversion wins a huge reward.* The price of Bitcoin should increase just due to the anticipation and speculation that some country might attempt to win the prize.* And the higher the price goes, the more valuable the reward becomes, so the higher the pressure to be the first to convert.
If Satoshi owns 1.5 million bitcoins, then giving away this reward should make his remaining bitcoins a thousand times more valuable.
I'm sure Satoshi wants Bitcoin to succeed.* This would be a way to increase the chance.* Perhaps we need better infrastructure first, like good, cheap hardware wallets?