So as time goes by, you ended up creating a jquery alternative. Now imagine you work on a large team and everybody ends up creating their own frameworks...
I think the above comment should be taken in the context of doing it for the sake of learning, not for putting it to use in actual projects.
That would be awesome since then everyone would learn A LOT about javascript. But to work together with other people, one of the first things to decide is the technology; and if you create something from scratch as a team, you do it together, not each one their own.
jQuery is not a framework, it's a collection of helper functions for the DOM.