You are wrong. All the posts about multi-boxers “crashing the servers” were about the lag produced on their own computer because of the large number of characters/spells needing to be rendered on individual computers. The number of players never caused an issue with the servers.
The lag issue player-side is why they don’t infinitely expand the servers. The Devs discussed this back when Classic first launched.
Your experience doesn’t include working with Blizzard’s code. The issue isn’t the servers. The issue is players’ computers.