I don't know if this topic has been raised previously however it's got me pondering.
Where do the little lamplitghters come from? Is it that the residents of BigTown dump their infants in the caves after they've been weened?
Surely the Lamplighters themselves can't be breeding amongst themselves although that isn't impossible since they do not leave the caves until they are 18?
Little Lamplight kicks people out at the ripe old age of 16. There's (AFAIK) one kid you can bring to Little Lamplight so they do take in non-Mungos who travel across the Wasteland to them - which I imagine can't be a large number of children. This gets really gross now - so you may want to stop reading. Otherwise, it's teenaged pregnancy.
200 years, starting with a classroom about 30 ish. Children born to 14 and 15 year old girls (probably 16 as well, I imagine that being pregnant might be an extenuating enough circumstance to allow a slight extension to your stay in Little Lamplight. So it's been about twelve or thirteen generations. No wonder why they're down to less than a dozen inhabitants. The descendants of a society of inbred teenaged moms that are forced to leave their babies before they start teething. That's Little Lamplight. Now if you'll excuse me, I have to go wash out my brain.