This all sounds like FUD to me. You might as easily complain about how much harder it is to refill the gas tank than swap the batteries a few times.

Lithium Ion batteries generally have a maximum optimal operating temperature of 122°F but will operate up to 176°F. If the temperature is approaching 176°F, I think the human will be the first thing to fail.

Also, nobody needs to lug around a full day of power. Spare batteries can stay in the truck until needed, at most you would have one spare on your person.

need to power a leaf blower all day

That's the magic thing in the word "replaceable". They are, you know, can be replaced. While you use one, the other is charging, and then you replace them. Just like, you know, construction workers are doing for the last at least three decades.

I was thinking in the context of a landscaping company driving to a bunch of different clients’ houses and doing general cleanup and maintenance, lawn mowing etc at each one. Electric lawnmowers now have dual battery packs that you can swap between, each one lasting about an hour. I wouldn’t expect a leaf blower to be much different in power requirements. Could probably even share the same battery design with the mower.

If you’re only doing an hour or less of leafblowing per client then you can just keep swapping batteries and have spares in the van/truck. For a really big job you might need more but then you could probably ask the client if you can plug your charger into their house to charge. I think a lot of people have outdoor outlets. Otherwise you could have a charger in the vehicle.

Use a rake?