That's definitely a potential issue - JavaScript is the fundamental standard, not JQuery and not TypeScript. Certainly there are situations where maximum forward-compatibility is important (learning resources are a good example) and for those, vanilla JavaScript is the best choice.
All of the old resources that relied on JQuery are now hopelessly outdated, whereas the contemporary ones that used plain JavaScript are as valid now as when they were written. I'm sure the same will be true of TypeScript vs JavaScript when the next big thing comes along.
True, but on the other hand, almost any JS code snippet written 20 years ago has better and more elegant alternatives today. APIs evolve all the time.
jQuery was so popular because writing anymore than a few lines of vanilla JavaScript was an *awful* experience due to all differences in browsers.
When things eventually standardized-ish and jQuery became unnecessary, other libraries/ecosystems popped up (e.g. React/JSX) to make writing webapps easier because writing anymore than a few lines of vanilla JavaScript was still an *awful* experience.
When webapps grew in size and scope, other "transpiled" languages popped up (e.g. TypeScript) because writing anymore than a few lines of vanilla JavaScript is *still an awful* experience.
We're stuck with JavaScript due to past decisions, but let's not pretend it's actually a good tool. If it were we wouldn't need 50,000 tools/frameworks/transpiled languages to hide how terrible it is.