In addition to being rare, helium is a non-renewable resource. The helium that we have was produced by the radioactive decay of rock, long ago. Once the gases is leaked into the atmosphere, it's light enough to escape the Earth's gravitational field so it bleeds off into space, never to return. We may run out of helium within 25-30 years because it's being consumed so freely.
Why would such a valuable resource be squandered? Basically it's because the price of helium does not reflect its value. Most of the world's supply of helium is held by the US National Helium Reserve, which was mandated to sell off all of its stockpile by 2015, regardless of price. This is based on a 1966 law, the Helium Privatisation Act, which was intended to help the government recoup the cost of building up the reserve. Though the uses of helium have multiplied, the law has not been revisited, so by 2015 much of the planet's stockpile of helium will have been sold at an extremely low price. Unless the price of the helium increases, there will be no perceived reason to conserve or recycle the gas so it will be used and lost. Will we run out? What do you think?