Ironically, http://youmightnotneedjquery.com/ makes a pretty good case in favour of jQuery.
If they just add $ notation, then there will be redundancy / inconsistency with existing api. Furthermore it will break / confuse apps which use jquery.
Then it's far easier to just include minified jquery into your apps when you want to use it, and you have more control about it's version, etc.
['map', 'find'].forEach(f => NodeList.prototype[f] = Array.prototype[f]);
document.querySelectorAll('bla').map(el => whatever)
['map', 'find', 'filter', 'reduce'].forEach(f => NodeList.prototype[f] = Array.prototype[f])
// this is for for..of, cannot be above 'map', 'filter' etc.
NodeList.prototype[Symbol.iterator] = Array.prototype[Symbol.iterator]
document.querySelectorAll('span').map(el => console.log(el))
document.querySelectorAll('span').filter(el => el.className === 'fc-black-500').reduce((acc, el) => (acc += el.className, acc), '')
for(let p of document.querySelectorAll('p')) { console.log(p) }
document.querySelectorAll('div')._.some(...)