ES6 already released. It is a current standard for almost a year and ES7 is coming. Probably you are confusing ECMAScript2015 (ES6) and ECMAScript 2016 (ES7).
Actually you should dropped jQuery since ES5 which added querySelectors, classLists, forEach and many other stuff. All your examples, are just old vanilla JS, even older then ES5. Still, of course, ES6, has new features also.
Yes, you should drop jQuery since it was invented 10 years ago in a time when we had problems with JS standard and it implementation. Every browser had own API and many DOM APIs were missed these times. jQuery use case was a simple cross-browser scripting and nothing changed. Now you don't have that problem. The jQuery problem is, you need to include at least jQuery core which is huge and vanilla JS, of course, is the fastest approach for browser scripting. Let be honest, we never needed jQuery in our apps, we needed widgets like autocompletes, select2, form validation and everything else. We imported jQuery only because those libraries asked for so. Problem here is that still today we have too less good Vanilla JS libraries but we have over 9000 same plugins for React/Angular and everything else. That's why I created https://bunnyjs.com - set of Vanilla JS librares, helpers and widgets. If you just want to display data from the server via ajax, you only need to import one small file and you are ready to go.