chiiisd_FB Very few translators can do 100 chapters singlehandedly a month. Probably only a handful can do so. The average speed for most translators these days is about 30-50 chapters a month.
Assuming the 100 chapters/month rate, a 3000 chapter novel split among 10 translators at 100 chapters a month in theory can be finished in 3 months. However, it's unlikely there are even 10 translators that have that speed.
Next, you need an overall editor to ensure that everything is consistent. And if you have ever read a 3000 chapter novel carefully, it will take about 2-3 months of reading alone because there's just so much text. The editor has even more work since they will have to read and edit each chapter individually (and probably sequentially), so the editing speed for 3000 chapters will end up taking 6 months or so, because a fast editor will take two times, if not more, than the reading speed. Again, we have to have only one editor to ensure consistency in style, naming conventions. If not, you end up with the same problems with having multiple translators.
That is what some translator groups do out there, and indeed, their speed is relatively fast. About 100 chapters a month. Besides, if a translator is that fast, they will likely prefer to do a book of their own because it is a lot more rewarding (not monetarily) to be responsible for one book. Being a part of a group doing a single book gives little sense of ownership to the project.
Also, the philosophy behind web novels is not to binge it and read in one sitting. It's meant to be read in tidbit sizes when you have little to do. Perhaps if there are more incentives like, micro-donations, increased earnings, translators will increase their release speed with time. That was how it worked 15 years ago in China. Authors released like 1 chapter (maybe 2-4 chapters worth in present day) a month. But with monetary incentive to write, authors began going full-time, and writing at consistent paces. The translation scene is pretty similar to what it was back then, though the speed at which it has progressed is a lot faster than how the author scene developed.