We had a bunch of Japanese teenagers run scripts on their computers and half the Fediverse was full of spam. If someone really cared about spamming, this shit wouldn’t stop as quickly.

The upside of that attack is that instance Admins had to raise their game and now most of the big instances are running anti-spam bots and sharing intelligence. Next time we'll be able to move quickly and shut it all down, where this time we were rather scrambling to catch up. Then the spammers will evolve their attack and we'll raise our game again.

It's true that the toolset isn't here now, and the network is actually very fragile at the moment.

It's also true that platform builders don't seem to want to deal with these kinds of tools, for raisins.

But it's also true that temporary blocks are both effective and not that big of a deal.

I'm not sure why you'd think that manual moderation will lead to small instances getting barred, though. Unless you're predicting that federation will move to whitelisting, rather than blacklisting? That's historically been the tool of corporate services, not personal or community ones.