"You are likelier to support taxes and condo fees to assist others, since you yourself are not stagnating or moving down the ladder."
It depends, but I generally agree. I would say the mentality should be that it benefits the community and not necessarily any one person.
"The other people on the other side of town who are poorer, for various reasons, simply will not get a park."
I don't think you understand just how small most small towns are. Many times there's only one park. If it is tribal at all, there tends to be only one tribe (or there are personal issues).
"we’ll raise money for our neighborhood park, but of course they have money since their ancestors got there first (or maybe worked harder?) and passed down their land or whatever other structural advantages."
The current generation (and previous one or two) are worse off than before. The mines and mills have shut down. The vast majority of the factories have been offshored. The industries that have replaced them, like tech, have mostly consolidated in just a handful of large cities. Most have little to no money.
The land you talk about is really a negative point. The family farms generally get divided when handed down. Or they simply are too small by today's standards. They get consolidated by corporations. The land in these areas isn't worth very much either ($500-1000 per acre).
So what assets they get handed down are diluted, and aren't worth much in the market (even depreciated). The structure has been going against them for decades (jobs move out, people move out, demand drops, prices drop). The region is severely economically depressed. These are people working and organizing to make their community better. This is what government should be. Not some distant vague entity that wants to solve everything through taxes.
Here's an example, in the area I'm in now I am part of an organization. They wanted a few trees cut down that weren't near anything. It would be easy to do. The people cutting them down could even use or sell the wood. It would be no risk and no cost to the organization. Instead they chose to hire someone at a cost of a few thousand dollars...