NLTK might not be the best example of this--it was originally written for pedagogical purposes[1]. One that was sorely needed, too, as in 2006 it was very difficult for a student in an intro to NLP class to easily track down and use existing implementations of various algorithms. NLTK continues to be useful for similar reasons today, as it provides the only relatively usable interface to some valuable but poorly engineered (by modern standards) academic resources such as FrameNet.

Anyway, original commenter seems to presuppose that there's no value in collating and polishing existing resources. Isn't that all, say, a Linux distro is? Is it true that "[Canonical] just wrap all the open source [code] into a [distro] and just want to sell the hype"? If it seems like curating and polishing has value on the market, maybe we ought to at least entertain the possibility that this value is not an illusion of marketing. That's why I agree with dang that OC is a facile dismissal.

Also worth noting that spaCy isn't just wrappers. spaCy's tokenizer, which is an original work, is used in at least two cutting-edge academic NLP libraries, AllenNLP (@AI2)[2] and Stanza (@Stanford)[3], presumably because using spaCy's tokenizer was better than the alternatives.

[1]: https://aclanthology.org/P06-4018.pdf

[2]: https://github.com/allenai/allennlp/blob/e0ee7f43d5da973e77d...

[3]: https://github.com/stanfordnlp/stanza/blob/68aa42653d656f613...