You might remember the io.js fork of Node.js back in 2014. Node was stagnating, a bunch of people forked it into io.js, which eventually got merged back into Node and got it back on track. Or, going further back, CoffeeScript, a "fork" of JS that had its best ideas adopted back into ES5.

A small scrappy team can prove out a good idea because failure is not a catastrophic risk to them. In short, forks are part of a healthy ecosystem.