1. remaking all the code and data
2. setting it up to work with the battlenet launcher
3. bug fixing
4. code fixing
5. optimization
6. making sure the security is more tight
7. intergrating systems that were not in that will need to be in like as i said battlenet chat and real id
8. setting up the servers, website, dev team, payment plan, launcher, addon API
9. testing
10. phsyical server settup
11. gm staff and dev staff specificly for this project
12. office space and set ups for this system type
13. many other things
you are legit stupid if you think this is a thing they can just go "ok we are gunna make vanilla servers" then they flip a switch and it is done
because it does not exist, it was patched out and over many years ago, it was changed tweaked and sundered.
they really have no reason to keep a complete backup of every single x.x.01 patch years after it was made.