Frameworks hurt sharing. I'd really like to give you this fork Jimmy, but you're gonna need a knife and plate to use it. The framework checks out all your girlfriends for you, the framework won't let anyone dirty get through, the framework will wait up until you get in, the framework will always find out were you've been, the framework keeps you healthy and clean. Frameworks embrace, extend and hold on to greedily.
Code wants to move. Code wants to be reused. Anything that slows down code from being reused, from moving around, is friction. Friction can come from many directions. For example, the license that code travels under can induce, or reduce, friction. Code written to a framework has higher friction than code built on top of libraries. That's not good or bad, but just one more facet you need to think about when writing code.