We already have available on our website an archive of everything from june (or july) 1996 on, including all CCD Astronomy issues, and Skywatch. I created them myself back in 2003, and we continue to add to it every month.
The problem with issues previous to that date, everything needs to be scanned, because it was pre-digital.
When I started in the ad department, I researched the price of digitizing everything from 1940 on, but at the time it was cost prohibitive.
As I'm not involved in the production end of the magazine, I don't know the current logistics.
I'm all for making a digital version available immediately when the issue is ready, perhaps as a supplimental to a subscription. How many readers would like to read the issue at the same time as everyone else, while still waiting for the US mail to slooowwwly come through?