Did you read the last line where I mentioned it was faulty logic?

Flat files and replication would probably get you unreasonably far.

I don't know why you are being down-voted. Premateralized flat files pushed out to heavy-duty CDNs would get you very, very far. I would think that dealing with CSAM, death-threats, and other things that would get your platform into trouble would be the more difficult problem to manage. I could very easily see the technical parts of Twitter being run with a few hundred people. I don't know what else would be involved for legal, finance, marketing, sales, etc. But I doubt it is 8,000+ people.

Did you actually read the whole comment you replied to?

also, iirc a database based architecture was why the failwhale image was made. iirc the threw out databases and went with something more analogous to email with tweets represented as files on file systems. That was was a lonnnng time ago though, they may have reinvented the architecture a dozen times since then.