Databases and traffic is going to have your lunch anyway. Good developers cost a good deal more than extra infrastructure. Adding people to help you cut cloud cost is easier and more predictable than re-implementing.

Bad developers will cost you more.

Discord also runs in cloud. They could save $$$ by just going to the colo instead

I doubt that, with that many users they would probably need to build their own stuff, around the globe. their servers have such a low latency, that this would be impossible by just going "colo".

peope who say that they can just save money in their colo are probably never even working in the scale of discord, which is fine.

Then you’d probably be shocked to find out that they already do that for voice servers. I’m talking about the other part which doesn’t have to have many geo distributed locations only a couple