You didn't have trees in lawns, basically. Look at the pictures of old English manors - there would be hedges next to grass lawns but the trees were few and far between in the lawns.

The areas of the garden with trees would be a different thing.

I don't know about England, but trees were common in American lawns since long before leaf blowers existed.

They didn't.

The standards to which we maintained things were far, far lower in the past because doing so was much more laborious and therefore expensive.

It works seem that those lower standards have no significant adverse effect. They only impact trivial stuff like aesthetics.

You couldn't slip on wet leaves and expect to sue the property owner back then.

How did people cope before cellphones existed? It's the same as my original point - it's a nonsense question. If you want to create additional work for people by doing it in a less technological manner, focus on the served in the society rather than underserved, who are trying to get a leg up in the economy.