Pasolini wrote a famous essay in 1975, "The Disappearance of the Fireflies," which, at that time, was already starting to become very noticeable. Of course, the essay was really about capitalism.
Personally, outside my childhood in the countryside, I noticed fireflies in the outskirts of a largish city some 20 years ago, then nothing for a very long time, and then I saw a few when I lived for a brief period of time in a really remote place, like an hour from the nearest highway. No trains anywhere near, too.

Off-topic, but if you don't know Pasolini, I urge you to read his last interview which seems particularly gloomy as it appears to foreshadow his own death just a few hours after.
One memorable quote:

I listen to the politicians – all the politicians – with all their little presumptions and I turn into a mad man as they prove they do not know which country they are talking about, they are as far away as the moon. And together with them there are the men of letters, the sociologists and the experts in any kind of field.

I've been so happy to see them in our yard this year. Enough so that I've stopped clearing brush just in case that's why they're here in such numbers. I haven't seen them like this in a decade or more.

Source? :(

Please I need to know!

I had wondered why we always seemed to have some fireflies here and it turned out my hatred of raking and leaving the leaves under the bushes helped a lot!

Lanternfiles, on the other hand... Oh, wait, oh fuck.

The dad then joins his son laying on the floor and crying

I convinced my inlaws to stop bagging or raking their leaves a few years ago, and they're everywhere now. Not as many as if the whole neighborhood has done it, but more than when I met them.

Wikipedia says the species near me (southern Ontario) are of Least Concern for extinction:

https://en.wikipedia.org/wiki/Photuris_lucicrescens

I miss seeing these everywhere in the summer as a kid. Guess I just aged myself lol, but I did see some in the park last night. Nowhere near as many as years ago though.

This is a wild concept to me. I see hundreds if not thousands every night in the summer.

I've seen them once in my life, in Smoky Mountains, about 10 years ago. It was pretty much spiritual experience. The darkness came alive. I cried when I saw their luciferase smeared over windshield and glowing long after the creature was dead. I knew lots of lore about them, saw them in mass culture - never realizing I never saw one myself, even though I take care to notice all living things around, from bacteria and yeast to mycchorizal networks.

I live in Europe.

!nativeplantgardening@mander.xyz

Alexa, play Owl City - Fireflies

More seriously, I'm pleased to see I'm not the only person who views this as a terrible loss.