Anyways, an interesting nugget is buried in that article. It says that a reason will o the wisp may have been common in the past is because lantern flames may have ignited the gas, which seems like a decent explanation. People use electric light everywhere now.

I guess another issue could be that there's so much ambient lighting from street lights and light being reflected off clouds that it's simply too bright for us to see anything. People back in the day probably experienced a lot more completely black nights.

It's completely possible that will o the wisp will be a completely forgotten phenomenon in a couple more decades, since I don't know anyone under 80 who's reported seeing it, and kids probably don't even know of it now. And it makes me wonder if there are other phenomenons that ancient people were very aware of but no living person has ever seen.

* People spending less time outside at night in general these days, bc indoors is where all the gadgets are

* When you do go outside at night, are your eyes going to be as dark-adapted as someone from say 1850 might have been? Shorter walks between brighter places these days could factor in.

* Swamps aren't as common as they used to be; particularly in the early 20th century in the US, swamps were frequently drained to 'improve' the land. Not as much decaying vegetation near at hand.

* Virtually everyone that dies these days is either chemically preserved, or cremated, so not as much decaying flesh in the cemeteries

[1] https://www.gutenberg.org/files/24430/24430-h/24430-h.htm#V