From the August 29, 2019 TSC meeting minutes:

[Delayed loading] is still in a state of limbo between the File SOP and VDB. One sticking point has been Windows support. Another is the difficulty to pass options to the IO translator.

There's only one thing I'm after with delayed-loading support and the file SOP which is the ability to adjust the display mode of the VDB to choose between "full geometry" and "leaf node bounding box". Without this option, cooking and displaying the file SOP with the viewport open forcibly loads all the data.

We could solve this problem with an additional downstream SOP that modifies the display state so that you set the display flag on this SOP instead of the file SOP and avoid the viewport load, but this very much goes against convention such as the "Display Packed As" option on the file SOP.

Perhaps JeffLait can comment on whether he'd also like to have an option to enable/disable delayed loading per file or the maximum size of the VDB in memory before it's copied to the local drive, I don't mind too much about this. I'd be happy for it to be a global setting.