Theoretically we're running out of Helium, just like we're theoretically running out of oil, but actually we've still got plenty left. Because of the US dumping their stocks the price has been artificially low making it unprofitable to extract from natural gas which contains a lot, and it has been just released in the atmosphere because of that instead of contained. As soon as prices start to reflect the extraction price there won't be a problem anymore.

This makes me wonder if these new hard drives will have a limited shelf life. I know they have spent so much research on keeping the He in, but it's more likely that they have just slowed down the leaking, so will this hard drive still be spinning in ten years? Some hard drives are expected to keep running for at least that long.

Also, I worry about air pressure changes. If a particularly nasty weather system came along with a very low pressure centre, and the hard drive is completely sealed, then it will have to either flex to accommodate the He expansion or be very rigid indeed. If it flexes, does that de-calibrate the head alignment? Is the case strong enough to deal with 200N force pulling it apart?

The problem with Helium, that it is small: therefore even glass acts as a porous sponge from that point of view.

Helium will inevitably diffuse and leak through over time.