Asklemmy

I'd like to push back a little on your second paragraph, as most of the listed things mentioned can be remediated with appropriate planning/actions. Of course every case is a different one, this always depends on the local context, but as a general rule:

Trees are expensive to maintain

If you plant native trees, that usually isn't a big problem, as they have been adapting themselves to those conditions for thousands of years

in addition to cracking sidewalks and roads

You can always select appropriate trees species that don't have such aggressive root system that tends to crack them

they need water

Once again, native trees are your best bet, in conjunction with water harvesting techniques, I don't think it will be a problem. I always recommend Brand Lancaster and Andrew Millison work on this subject. See Harvesting Rain Water for more details

If you prefer video format:
"Free water was illegal... He changed that..." [19m15s]
YT link, non YT link

the leaves need to be cleaned up

I always find this a weird obsession, why do we have to clean them up? In a forest, it usually lies on the floor and becomes nutrients, habitat, reduces water evaporation from the soil, protects the soil from erosion, etc

they need to be trimmed

This one depends a lot on the context, but at least around here, trimming usually means butchering trees and making them completely unbalanced, which makes the population even more upset as your point below becomes the likely scenario

they pose a liability risk so need to be covered by insurance

Healthy trees are not likely to cause problems. Again this one depends on how the city deals with it, but routine check ups should be more common

Considering all the benefits greenery has in our lives, I still think we come out way ahead with it in the long term, even if we were only looking at it from an economic perspective