Large, high-enrollment computing courses are adopting more structured approaches to supporting students, but questions remain about which structures effectively support teaching and learning. We present a mixed-methods investigation of a large CS2 course that leverages a Student Support System (SSS), which combines flexible extensions with one-on-one support meetings. Through behavioral profiling of student engagement and thematic analysis of support staff interviews, we find that while the SSS expanded access, fostered human connection, and reached underrepresented students, it failed to produce equitable academic outcomes. Our findings reveal the limits of reactive, human-dependent support at scale and highlight suggestions for redesigns. We invite further discussion on where well-intentioned systems like the SSS can fall short and what improvements are needed.