I take the original comment to be that file syncing will never be a product on it's own. The market for people who need file syncing on its own is small and it only really becomes useful for a large number of paying customers when it is something embedded into a more directly useful product (like GSuite or Office 365). And I think he's been largely right. It's common on HN for people to complain about how Dropbox was great when it did just one thing really well but they weren't a profitable company doing one thing really well. They always needed to create a broader product on top of file syncing in order to survive as a standalone business.