I didn't expect to be writing this comment on this article hah, but apparently there is such a thing called a surge tank for storing boost pressure to mostly eliminate turbo lag:

https://www.highpowermedia.com/Archive/the-surge-tank

https://forums.tdiclub.com/index.php?threads/air-tank-or-com...

It's such an obvious idea that I'm kind of shocked it took them until 2003 to do it. Surely someone thought of this in like the 60s.

I would probably do it differently with a separate supercharger to intermittently maintain another 1-2+ bar of boost to make the tank less than half as large, but that would add complexity, and what do I know.