Agreed, life is not always zero-sum, and higher taxes don't always translate to better services.
Let's look at an example of where life is zero-sum, which also happens to be an important battleground that leads to more macro effects: wage negotiations. Clearly it's zero-sum: the firm produces some wealth, and many dollars that aren't paid to wages end up paid to someone with more power in the firm, such as an owner, major shareholder, or executive.
Now, when it comes to negotiating wages, in an oversaturated labor market, workers without a union are in a terrible bargaining position, as they basically have the choice: work or die. This leads to what we see today: horrible exploitation of the people with the least power in society. Lawmakers have, over the years, stripped unions of relative power. This is one of the choices I mentioned, where one group is immiserated precisely in order to let another group hoard more and more money. Now, sure, unions have downsides, and they can be corrupt, but on the whole, US wages have stagnated while production has increased since the 70s, when the US began its forceful destruction of labor power.
The only argument you can make in response is that the system as a whole has to be this way, or else, for example, talented executives won't step up to difficult tasks and things won't get done. I'm sure that, in some cases, this is true, but it's a trade-off, like most other things in economics, and the absolutist way that many people hold this, so that a lot of exploitation is justified to retain this, is murderously excessive, and not based on empirical evidence.
