For example, you can take a group of five billionaires. Give the first four a little tax break for something, which totals up to only be a million each. No big deal, right? All these people are the 1% of the 1% of the 1%, the pinnacle of wealth in the world. There's no way that little tax break would prevent the 5th billionaire from buying the private island he always wanted, or whatever.
In practice, though, that 5th billionaire will be pissed he didn't also get the tax break. He will spend a lot of time either angry at the situation, or spending that time also trying to get a tax break. Is that a good use of his time? He would be happier driving around on his 80ft yacht... if he could focus on that instead. But that's not how our brains are wired.