> 4) Performance evangelists and salesmen will try to convince everyone they need to get a response in 50ms, but for most use cases that's just ridiculous. Most people are fine getting a response in under a second. Just use a CDN for your static assets and your monolith will be fine.

That would be true if loading website was just single request. But today web apps load multiple requests and probably even more in the background since so many use microservices. When you say 200ms it sounds fast enough, but usually end result is between 3 and 5 seconds combined. If every request would go from 200 ms to 50 ms, total load time would be closer to 1 second, which is fast enough.