Scale-Up vs Scale-Out: Why Every Language Wins Somewhere

I worked with a team that rewrote a critical service from Go to Rust because "performance." Six months later, the service was 30% faster, the team was miserable, and feature velocity had dropped to a crawl. Meanwhile the competitor team, still on Go, had shipped four new features. We did the postmortem eventually. The service handled maybe 2,000 requests per second on a 4-core machine. CPU utilization sat around 20%. Rust's extra speed bought us exactly nothing — the bottleneck was downstream da