There's a big difference between a technical issue and a security issue.
It should be obvious by now that Apple has intentionally shut down the Dev site because they are investigating a security breach.
Every normal update has a rollback option that can be put to work when something goes terribly wrong.
Apple would certainly be able to return to status quo if it wa just an update.
The are probably checking how much data might be compromised and what attack vectors led to the breach.
This is not a technical issue. Even the smallest company in the world would be able to get something up and running again within 3 days.
Even with all Provisioning Profiles and Certificates wiped from their databses.
They could simply say "Sorry, re-create your certificates and profiles."
But they don't.
They are probably still under attack monitoring connection attempts and access patterns.
PS: If you consider that most devs pay for iOS and Mac dev center access, that's 200$ per year per dev.
How many registered devs did they announce at the keynote? I'd be happy to have that amount of money as annual revenue 😉