I can't speak for anyone else, but that is what I would call resource-intensive.
My proposed idea isn't very resource intensive at most it would take about a dozen servers.
It's a good idea, but I'm not sure why Canonical (I think this is who you're aiming this at) would need to support this: you can already do this manually yourself with a little bit of command-line (no doubt there is a GUI program somewhere to do it if you look hard enough):
If for whatever reason a user wants to do a fresh install on a different computer and doesn't have a copy of each program name, the sources, and libraries this service I'm proposing would solve that.
On the machine before a reinstall will produce a file you can backup with a list of installed packages.
dpkg --get-selections > some_file.txt
After a catastrophic failure, you could then restore your backup of your list of installed packages, then install them all at once.
Although I can see where you're coming from, it would be handy if this got implemented.
sudo dpkg --set-selections < some_file.txt
sudo apt-get -u dselect-upgrade