Hi,
My 2 cents and a quick remark.
More and more often, Wikisources use the proofread page extension (which allows to ensure good quality and help working together through microtasking).
This extension is obviously not mandatory (if you look at
https://phetools.toolforge.org/statistics.php the average is 40% of pages with a scan and only 18 of the 70 wikisources are above this average) *but* there is strong correlation between the percentage of pages with scan and the activity/strength of the community ; I guess using the Proofread page extension should be promoted.
There is a probably trade-off to find between interfering and letting a community grow on its own...
All in all, this project seems to be indeed quite active and should be approved in middle- if not short-term. But maybe "someone" should contact and encourage them to use more the proofread page extension.
Cheers,
~nicolas