I see the people leafblowing in the picture are not using ear defenders either , I typically use a set of ear plugs with ear muffs over the top when Im using noisey garden equipment .
The regulations in built up areas ,like California simply dont apply in rural areas , not to mention the difficulty of trying to police regs down on the farm .
Ive heard of stories from large beef farmers in Ireland and the rising number of regulations ,paper work, general red tape and spot checks by department officials making whats already a tough job even more difficult .
In garden equipment places here they do sell other special fuels specifically to cut down on emissions from small two stroke motors , Im not sure the formula . Another thing they could try is running this kind of gear on ethanol/castor oil , although port timing and carb jet modifications would be needed to make them run nice , its definately one possible solution in built up areas .
This idea that we could simply swap over to battery power might be fine in the domestic sector of the market but its never going to be a viable option for commercial operators , they'd need a wheelbarrow load of batteries and associated chargers to do the same work as a couple of cans of gas .
I typically run my ride on mower as late into the winter as I can , of course the grass has stopped growing , but its a usefull way of hoovering up leaves which are then added to my compost heap .