Is it reinventing the wheel, or is it making a new wheel that exactly fits the design requirements?
A framework with all the bells and whistles isn't that great when I want a framework with a piano.
A framework with all the bells and whistles isn't that great when I want a framework with a piano.
Changing someone else's (meaning an external third-party) code can be as easy and fun with the right tooling, but the tooling around supporting that tends to be really bad in most ecosystems. There is a common assumption found around dependencies that their code is theirs and shouldn't be touched except by the hand of the original author.
Not impossible to overcome, of course, but with enough friction that you have to seriously consider if it beats simply writing your own. A little copying is better than a little dependency, but a where there is a lot of copying...