Much like a clogged artery, interest-specific legislation has slowly accumulated in the legal code, blocking progress and undermining the health of the system.
Would you be surprised to hear that our government is just like a middle-aged American who, having eaten fast food for decades, now faces heart trouble in his golden years? Aging nations have arteries clogged with obsolete laws, slowing blood flow and preventing oxygen from reaching all parts of the body politic. Physicians call this arteriosclerosis; historians see decline of empire.
Congress has been on autopilot for so long that we have forgotten how to fly the plane manually.
It happens so slowly and naturally that no one notices. Legislators want to prove that they care about children, seniors, veterans, etc. by creating programs to benefit them. Elected officials are so busy campaigning that they (and their staffs) don't review the statute books to see which programs already exist. They certainly don't check to see which ones are working, and which are not. As a result, each new generation of politicians simply adds another layer of spending and bureaucracy.
Immortality awaits the legislator fortunate enough to have a significant law named after him. Think of Pell grants or Stafford loans for students, Sarbanes-Oxley to regulate Wall Street, or the Hyde Amendment on abortions.
Conversely, there's little or no reward in repealing laws, only the risk of offending people who benefit from the existing programs. Any politician who's ever been re-elected knows that friends come and go; enemies accumulate.