These are all good reasons why RBC would seem less awesome than Mini-Camp, but they aren't actually good reasons why it should have been less effective at teaching people rationality. If anything, surely one would expect people who were younger and had less going on in their lives to benefit more from rationality training.

Basically, I agree with you that these are the reasons that Eliezer describes RBC as "less of a success", but this just means that Silas is right, and the measure of "success" being used is "how awesome did everyone think it was", not "how much rationality did we manage to teach".