I'm pretty sure that's the case at UC too. I don't know UC, but at my 4 year engineering school it felt like 25% attrition every year; if you only do a year and drop out, better to not be paying enormous student loans for probably the rest of your life for that.
If you do two or three years and drop out, better to have a degree, even if it's just an Associates.
If you know you'll make it all the way to a Bachelors, yeah, maybe it'd be better to go direct. But even then, you might get smaller class sizes (and better experiences) at a CC because of the relative levels of the student bodies. Lots of people taking calculus based physics of mechanics at a UC and not so many at a CC, so the UC might do lectures in a hall but the CC might have it in a classroom.