From LearnLiberty.org: “Why do politicians never seem to cut government spending? Using public choice economics, or the economics of politics, Prof. Ben Powell shows how voters are rationally ignorant of what politicians do. This leads to a phenomenon called ‘concentrated benefits and dispersed costs,’ which favors recipients of government payments at the expense of the average taxpayer.”
We see this type of behavior every day, in government at all levels. The people who seek subsidy at the public trough are highly motivated to seek it, and they will go to great lengths and expense to obtain it. The bureaucratic and political classes, both of which benefit from the subsidies, are motivated, too. Everyone else is less motivated, because the expense of most programs to them is very small.
This imbalance in interests is part of the reason why government tends to grow, and why cutting anything at all is very difficult.