It is better to think of a vacuum within air to be similar to a bubble underwater.

Air is like water in other ways too. We slightly "float" in air by the weight of air we displace. e.g. 80kg person is approximately 80 litres (density of a body is 1.010 kg/litre). Weight of displaced air is approx 0.1 gram (1.2929 gram/litre). So the floating effect of air reduces your weight (not mass) by about 0.1%.

> It is better to think of a vacuum within air to be similar to a bubble underwater.

I don’t think it is vey similar. That bubble pushes against the water to maintain itself; it manages to do that only because its “push” increases the higher its pressure and it is more compressible than water.

The vacuum, on the other hand, is compressible (if you want to call that so), but its “push” remains zero if you do, so it needs help to push against the air to maintain itself.

That’s why the post your replied to said “vacuums tend to collapse on themselves, I think it might be more costly in structural elements to prevent that?”

Thermoses have vacuum in the walls, and they are very thin, much thinner than a hard-drive case.

I think they do get designed specially for resisting the vacuum collapsing the walls, but you're right, it can probably be done!

What about a partial vacuum?

Perhaps there is a hapy medium between air resistance and cushioning? Reducing the air by an amount might help.

Although, I'd be surprised if they hadn't thought of this already :)

a partial vacuum of only helium, tightly sealed to keep in the helium. The tight seals will work to make sure that when there is leakage, only helium leaks in. and if there is no helium component to the air outside, you'll just get helium leaking out thus improving your vacuum.