I thought lightning bugs were mostly from light pollution and deforesting? I live in the woods not near a major city, and every summer there's thousands of them still, thankfully.

On the other hand, I don't think I know any millenials that don't have an extremely overbearing HoA that forbids anything other than a grass lawn.

Maybe not directly, but they definitely care about property value which gets you municipal codes requiring you to mow your lawn or get fined.