Currently they bring their own fuel to worksites. What happens when there's no outlet for them to plug into? There are large numbers of landscaping scenarios where this will be the case. Do they bring a diesel generator?

All of my yard tools, including my lawnmower, are electric. For reasons of both cost and power, I went with corded rather than battery powered. Battery tech is constantly improving and maybe at some point it will get to the point where it is viable for a yard like mine but for people who are doing a large number of properties per day, it's going to be quite a while.

Seems like the better interim solution would be making the small engines used by these tools emit less. This would of course increase the complexity and cost but seems like a better tradeoff than extension cords with large voltage drops, diesel generators, or lugging around half a dozen times more batteries than devices.

I can see it now. Some dude sitting around drinking coffee waiting for his gear to charge plugged into a gas powered generator.

Yes. In the State of regular rolling blackouts, and electrical grid sparked wildfires.

Nothing could possibly go wrong.

Electric equipment is just not practical or realistic for these landscaping operations where you are working 50-60 hours a week. They would have to replace batteries constantly as they get worn out from being constantly depleted and charging. Not to mention you would have to run your chargers off a generator in the truck bed anyhow, negating any green benefit since these things are noisy and pollute just as much as a hand tool. If they didn't need power offered by commercial grade gas equipment, they would be using cheaper handheld blowers rather than heavier and more expensive backpack models. Plus brands like STIHL are practically bulletproof in terms of reliability.