I have read this, too. I believe the US Govt actually had a strategic supply of helium for airships, no longer maintained, but some medical devices, MRI scanners, I believe, are dependent on having helium. Once released, it travels to the top of the ionosphere and is lost to us. Never mind no more 2m balloon bonanza cock-ups, we should be saying no more helium balloons: Just because we can, it doesn’t mean we should.