So who are these select few? They are indeed a small group, but not an inconsequential one. They include party leaders who benefit from centralized control of policy and personnel resources, lobbying groups with policy capacity to lend, and anybody who doesn't want Congress to be able to produce new legislation or know much about it if it does. That's about it.
Congress has given itself a lobotomy over the past three decades. It has eliminated thousands of staff positions, eviscerated its ability to carry out policy analysis, and generally has such low pay and difficult work environments that it relies on inexperienced and overstretched 20-somethings for the vast bulk of its work.
Before puzzling why any institution would do something so self-destructive and attributing the cause to irrationality or worse, we should consider perhaps that the system is now working just as many people would prefer.
Congress would significantly improve its problem-solving capacity under a reempowered committee system, with more and more professional staff to conduct policy analysis. Under such a system, committees have both the resources and the breathing space to tackle public problems. Congress would get more discovery on a range of problems, more information about potential policy solutions, and more capacity to solve problems.
By contrast, centralization of resources in party leadership means that information sourcesare tightly controlled, limited, and drawn into the zero-sum nature of partisan conflict. It's no wonder Congress is frequently incapacitated.
But change is hard.