There's also a huge difference between "how much does a college degree help an individual programmer" and "how much does a policy of requiring CS degrees improv

There's also a huge difference between "how much does a college degree help an individual programmer" and "how much does a policy of requiring CS degrees improve programmers as a class". I'd argue that there's more of the first than the second - a college degree is a largely a positional good in that having a more impressive educational background gets you hired only as much as other folks have less. I don't think the program is worth the massive investment getting put into it. There's obviously superior alternative structures - proctored algorithms tests to filter for IQ/ability, which qualifies you for a year-long apprenticeship with a working programmer.