biab-user,

I feel your pain. They definitely should have a way to download all demos for such situations.
A single archive updated yearly.

I requested offline demos at least half a dozen times, but your post clearly shows that it is not a "wish" or "request". It is a shortcoming that needs to be addressed.

P.S. One of the ways they can do it, is split the archive in 2-3 parts and offer download through internal BIAB download manager.