Unfortunately idiots who will run the mower over their own cord, or absent minded who consistently forget to plug the thing in to charge it, also exist.

And more neutrally there is a certain laudable economy in not throwing away a perfectly functional lawn mower just because it's become a relative nuisance as the options around that have become better over time. The lawn mower equivalent of wanting to drive a car until the wheels fall off because why trash a perfectly functional car when so many people don't even have that.

Finally there are other people who actually enjoy the petty power thrill that comes with being able to make all of their neighbors endure the harsh grating drone of a 2 stroke engine, the kind of person who doesn't see the problem with suggesting other people should wear earplugs in their own homes when he's mowing his lawn, (there's a number of this type in this very comment section doing the same for cars) and because there is a flimsy but historically normalized justification for it -before electric mowers appeared on the market, everyone else with lawns to cut had to be equally guilty of making a comparable racket willing or not- they get away with it as there's no straightforward legal argument that isolates exactly why what they're doing is a net harm to the quality of life of all their neighbors.