Mostly through either self-inflicted pain of languages that got its concurrency primitives wrong or ended up having it too complex to be useful before we arrive

Mostly through either self-inflicted pain of languages that got its concurrency primitives wrong or ended up having it too complex to be useful before we arrived upon better ways. Naturally, this is not to say the language designers were bad at it, far from it! It just took the benefit of the hindsight and time due to non-uniform knowledge propagation throughout the industry to nail them down as can be seen in Rust and C# in the form of async/await and Futures+Tasks and CSP-style in the form of Elixir and Go. Today, Rust makes it trivial (given the tradeoffs) to achieve such even in bare metal scenarios with custom executors, while C# offers zero-effort model for general purpose scenarios: using var http = new HttpClient(); var req1 = http.GetStringAsync("https://news.ycombinator.com"); var req2 = http.GetStringAsync("https://lobste.rs"); Console.WriteLine(string.Concat(await req1, await req2));