Final answer:
Issue networks have become more prevalent than iron triangles due to the increasing complexity of policy problems requiring more inclusive and diverse input from various interests and stakeholders.
Step-by-step explanation:
The prevalence of issue networks over iron triangles can be attributed to the increasing complexity of policy problems. Issue networks are a broader and more open pattern of interest group politics that include a range of different interests and political actors than the more structured and exclusive iron triangle, which consists of a symbiotic relationship among Congressional committees, executive agencies, and interest groups. Over recent decades, changes such as more professional lobbying, the fragmentation of interests, and many new interests developed due to technological advances have contributed to the shift towards issue networks. The rise of corporate lobbying, the diversity of interest groups, and the influence of PACs also support this trend.
Iron triangles have historically provided significant access and influence for specific interest groups closely aligned with particular agencies and Congressional committees. However, as policy issues have become more complex and numerous, it has become more challenging for these exclusive arrangements to address the wide range of contemporary policy problems effectively. The issue network model allows for more fluid participation of various interests and stakeholders, reflecting the growing need for inclusive and comprehensive policy analysis and decision-making.