> The lack of developers and thus slow pace of improvement [...] we are reliant on one or two volunteers to improve the product

I'm not sure why you have that impression. Zotero has amazing, invaluable volunteers, but there's a paid, full-time dev team working on Zotero every day. In the last year, we've added:

- Google Docs integration [1]

- Unpaywall integration [2]

- A new, greatly improved PDF recognition system [3]

- Faster citing in large documents [3]

- A much more powerful saving interface [4]

- Mendeley import...

- ZoteroBib, a free web service for generating bibliographies [5]

- A barcode scanner for iOS [6]

- Regular updates and bug fixes [7]

[1] https://www.zotero.org/blog/google-docs-integration/

[2] https://www.zotero.org/blog/improved-pdf-retrieval-with-unpa...

[3] https://www.zotero.org/blog/zotero-5-0-36/

[4] https://twitter.com/zotero/status/991052142717886464

[5] https://www.zotero.org/blog/introducing-zoterobib/

[6] https://www.zotero.org/blog/scan-books-into-zotero-from-your...

[7] https://www.zotero.org/support/changelog

(Disclosure: Zotero developer)